arm64: defconfig: Enable OF_OVERLAY option

The RP1 driver uses the infrastructure enabled by OF_OVERLAY config
option. Enable that option in defconfig in order to produce a kernel
usable on RaspberryPi5 avoiding to enable it separately.

Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20250529135052.28398-12-andrea.porta@suse.com
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>

Author: Andrea della Porta

arch/arm64/configs/defconfig

@@ -1665,6 +1665,7 @@ CONFIG_FPGA_BRIDGE=m
 CONFIG_ALTERA_FREEZE_BRIDGE=m
 CONFIG_FPGA_REGION=m
 CONFIG_OF_FPGA_REGION=m
+CONFIG_OF_OVERLAY=y
 CONFIG_TEE=y
 CONFIG_OPTEE=y
 CONFIG_MUX_GPIO=m