arm64: dts: broadcom: rp1: drop RP1 overlay

RP1 support loaded from overlay has been dropped from the driver and
the DTB intended to be loaded with the overlay no longer exists.

Drop unused include file and overlay.

Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/85167b815d41ed9ed690ad239a19de5cd2e8be1c.1766077285.git.andrea.porta@suse.com
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>

Author: Andrea della Porta

arch/arm64/boot/dts/broadcom/Makefile

@@ -13,8 +13,7 @@ dtb-$(CONFIG_ARCH_BCM2835) += bcm2711-rpi-400.dtb \
 			      bcm2837-rpi-3-b.dtb \
 			      bcm2837-rpi-3-b-plus.dtb \
 			      bcm2837-rpi-cm3-io3.dtb \
-			      bcm2837-rpi-zero-2-w.dtb \
-			      rp1.dtbo
+			      bcm2837-rpi-zero-2-w.dtb
 
 subdir-y	+= bcmbca
 subdir-y	+= northstar2