Fix ST7920_DELAY_2 potentially being unset

Comes from #7760

Marlin/src/pins/pins_SANGUINOLOLU_11.h

     #ifndef ST7920_DELAY_1
       #define ST7920_DELAY_1 DELAY_0_NOP
     #endif
-    #ifndef ST7920_DELAY_3
+    #ifndef ST7920_DELAY_2
       #define ST7920_DELAY_2 DELAY_3_NOP
     #endif
     #ifndef ST7920_DELAY_3