[Keyboard] Add 60_hhkb layout to hhkb (#8618)

Signed-off-by: Joshua Rubin <me@jawa.dev>

keyboards/hhkb/hhkb.h

@@ -21,6 +21,7 @@
     { K70, K71, K72, K73, K74, K75, K76, KC_NO }                               \
 }
 
+#define LAYOUT_60_hhkb LAYOUT
 
 #define LAYOUT_JP(                                                             \
     K02, K32, K62, K22, K12, K52, K72, KA2, K92, K82, KB2, KE2, KF2, KD2, KC2, \

keyboards/hhkb/rules.mk

@@ -67,3 +67,5 @@ endif
 # debug-off: EXTRAFLAGS += -DNO_DEBUG -DNO_PRINT
 # debug-off: OPT_DEFS := $(filter-out -DCONSOLE_ENABLE,$(OPT_DEFS))
 # debug-off: all
+
+LAYOUTS = 60_hhkb