Correct parsing of rules.mk for keyboard revisions

Previously, when looking for rules.mk files, we'd parse the individual
folders (A/B/C/D/E) into 5 variables, (A/B/C/D/E, A/B/C/D, A/B/C, A/B,
and A). Then, we'd get the final directory names and store _those_ in 5
new variables (A, B, C, D, and E). Then, when looking for the rules.mk,
we'd look in root_dir/keyboards/(A|B|C|D|E)/rules.mk, instead of looking
in root_dir/keyboards(A|A/B|A/B/C|A/B/C/D|A/B/C/D/E)/rules.mk. This
commit changes that logic from the former to the latter.

Makefile

@@ -307,11 +307,6 @@ define PARSE_KEYBOARD
     KEYBOARD_FOLDER_PATH_3 := $$(patsubst %/,%,$$(dir $$(KEYBOARD_FOLDER_PATH_2)))
     KEYBOARD_FOLDER_PATH_4 := $$(patsubst %/,%,$$(dir $$(KEYBOARD_FOLDER_PATH_3)))
     KEYBOARD_FOLDER_PATH_5 := $$(patsubst %/,%,$$(dir $$(KEYBOARD_FOLDER_PATH_4)))
-    KEYBOARD_FOLDER_1 := $$(notdir $$(KEYBOARD_FOLDER_PATH_1))
-    KEYBOARD_FOLDER_2 := $$(notdir $$(KEYBOARD_FOLDER_PATH_2))
-    KEYBOARD_FOLDER_3 := $$(notdir $$(KEYBOARD_FOLDER_PATH_3))
-    KEYBOARD_FOLDER_4 := $$(notdir $$(KEYBOARD_FOLDER_PATH_4))
-    KEYBOARD_FOLDER_5 := $$(notdir $$(KEYBOARD_FOLDER_PATH_5))
 
     KEYMAPS :=
     # get a list of all keymaps
@@ -325,29 +320,29 @@ define PARSE_KEYBOARD
         $$(KEYBOARD_FOLDER_3) $$(KEYBOARD_FOLDER_4) $$(KEYBOARD_FOLDER_5), $$(KEYMAPS)))
 
     KEYBOARD_LAYOUTS :=
-    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_5)/rules.mk)","")
+    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_5)/rules.mk)","")
       LAYOUTS :=
-      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_5)/rules.mk)
+      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_5)/rules.mk)
       KEYBOARD_LAYOUTS := $$(sort $$(LAYOUTS) $$(KEYBOARD_LAYOUTS))
     endif
-    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_4)/rules.mk)","")
+    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_4)/rules.mk)","")
       LAYOUTS :=
-      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_4)/rules.mk)
+      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_4)/rules.mk)
       KEYBOARD_LAYOUTS := $$(sort $$(LAYOUTS) $$(KEYBOARD_LAYOUTS))
     endif
-    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_3)/rules.mk)","")
+    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_3)/rules.mk)","")
       LAYOUTS :=
-      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_3)/rules.mk)
+      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_3)/rules.mk)
       KEYBOARD_LAYOUTS := $$(sort $$(LAYOUTS) $$(KEYBOARD_LAYOUTS))
     endif
-    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_2)/rules.mk)","")
+    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_2)/rules.mk)","")
       LAYOUTS :=
-      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_2)/rules.mk)
+      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_2)/rules.mk)
       KEYBOARD_LAYOUTS := $$(sort $$(LAYOUTS) $$(KEYBOARD_LAYOUTS))
     endif
-    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_1)/rules.mk)","")
+    ifneq ("$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_1)/rules.mk)","")
       LAYOUTS :=
-      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_1)/rules.mk)
+      $$(eval include $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_1)/rules.mk)
       KEYBOARD_LAYOUTS := $$(sort $$(LAYOUTS) $$(KEYBOARD_LAYOUTS))
     endif