Move and update check to ensure only one unicode method is enabled

quantum/process_keycode/process_unicode_common.h

@@ -18,6 +18,10 @@
 
 #include "quantum.h"
 
+#if defined(UNICODE_ENABLE) + defined(UNICODEMAP_ENABLE) + defined(UCIS_ENABLE) > 1
+  #error "Cannot enable more than one unicode method (UNICODE, UNICODEMAP, UCIS) at the same time"
+#endif
+
 #ifndef UNICODE_TYPE_DELAY
 #define UNICODE_TYPE_DELAY 10
 #endif

quantum/quantum_keycodes.h

@@ -81,9 +81,6 @@ enum quantum_keycodes {
 #endif
     QK_MOD_TAP            = 0x6000,
     QK_MOD_TAP_MAX        = 0x7FFF,
-#if defined(UNICODEMAP_ENABLE) && defined(UNICODE_ENABLE)
-    #error "Cannot enable both UNICODEMAP && UNICODE"
-#endif
 #ifdef UNICODE_ENABLE
     QK_UNICODE            = 0x8000,
     QK_UNICODE_MAX        = 0xFFFF,