[AVR32] Add mach-specific Kconfig

Include at32ap-specific Kconfig file from top-level Kconfig file. The
at32ap Kconfig is currently empty, but it will grow some machine-
specific options soon.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

arch/avr32/Kconfig

@@ -116,6 +116,8 @@ config	LOADER_U_BOOT
 	bool "U-Boot (or similar) bootloader"
 endchoice
 
+source "arch/avr32/mach-at32ap/Kconfig"
+
 config LOAD_ADDRESS
 	hex
 	default 0x10000000 if LOADER_U_BOOT=y && CPU_AT32AP7000=y

arch/avr32/mach-at32ap/Kconfig

+if PLATFORM_AT32AP
+
+menu "Atmel AVR32 AP options"
+
+endmenu
+
+endif