Add bootloader size (#13729)

* Add bootloader size

Bootloader size needs to be 6144 to allow QMK to jump to the correct location with bootmagic

* Include dz60rgb v2.1

Add boot loader size to this pcb also

keyboards/dztech/dz60rgb/v2_1/rules.mk

@@ -3,6 +3,7 @@ MCU = atmega32u4
 
 # Bootloader selection
 BOOTLOADER = lufa-ms
+BOOTLOADER_SIZE = 6144
 
 # Build Options
 #   change yes to no to disable

keyboards/dztech/dz65rgb/v3/rules.mk

@@ -3,6 +3,7 @@ MCU = atmega32u4
 
 # Bootloader selection
 BOOTLOADER = lufa-ms
+BOOTLOADER_SIZE = 6144
 
 # Build Options
 #   change yes to no to disable