soc: apple: Always include Makefile

We want to allow the code inside drivers/soc/apple to be compiled with
COMPILE_TEST but this will currently result in linking errors because
ARCH_APPLE is not set and make will never recurse into
drivers/soc/apple.
Let's just unconditionally recurse into apple/ since all drivers
in there are guarded by config options anyways.
Signed-off-by: Sven Peter <sven@svenpeter.dev>

drivers/soc/Makefile

@@ -4,7 +4,7 @@
 #
 
 obj-$(CONFIG_ARCH_ACTIONS)	+= actions/
-obj-$(CONFIG_ARCH_APPLE)	+= apple/
+obj-y				+= apple/
 obj-y				+= aspeed/
 obj-$(CONFIG_ARCH_AT91)		+= atmel/
 obj-y				+= bcm/