Define ST7920 delays for board ARMED (#12161)

Marlin/src/lcd/dogm/ultralcd_st7920_u8glib_rrd_AVR.cpp

   #define CPU_ST7920_DELAY_1 DELAY_NS(0)
   #define CPU_ST7920_DELAY_2 DELAY_NS(0)
   #define CPU_ST7920_DELAY_3 DELAY_NS(0)
+#elif MB(ARMED)
+  #define CPU_ST7920_DELAY_1 DELAY_NS(0)
+  #define CPU_ST7920_DELAY_2 DELAY_NS(0)
+  #define CPU_ST7920_DELAY_3 DELAY_NS(0)
 #elif F_CPU == 16000000
   #define CPU_ST7920_DELAY_1 DELAY_NS(0)
   #define CPU_ST7920_DELAY_2 DELAY_NS(0)