ARM: sunxi: Split the various SoCs support in Kconfig

This will allow to better isolate various options, and reduce the overall
kernel size if we're interested in only one of the SoCs.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

arch/arm/mach-sunxi/Kconfig

-config ARCH_SUNXI
-	bool "Allwinner A1X SOCs" if ARCH_MULTI_V7
-	select ARCH_HAS_RESET_CONTROLLER
+menuconfig ARCH_SUNXI
+	bool "Allwinner SoCs" if ARCH_MULTI_V7
 	select ARCH_REQUIRE_GPIOLIB
-	select ARM_GIC
-	select ARM_PSCI
 	select CLKSRC_MMIO
 	select GENERIC_IRQ_CHIP
-	select HAVE_ARM_ARCH_TIMER
 	select PINCTRL
 	select PINCTRL_SUNXI
-	select RESET_CONTROLLER
 	select SUN4I_TIMER
+
+if ARCH_SUNXI
+
+config MACH_SUN4I
+	bool "Allwinner A10 (sun4i) SoCs support"
+	default ARCH_SUNXI
+
+config MACH_SUN5I
+	bool "Allwinner A10s / A13 (sun5i) SoCs support"
+	default ARCH_SUNXI
+	select SUN5I_HSTIMER
+
+config MACH_SUN6I
+	bool "Allwinner A31 (sun6i) SoCs support"
+	default ARCH_SUNXI
+	select ARCH_HAS_RESET_CONTROLLER
+	select ARM_GIC
+	select RESET_CONTROLLER
+	select SUN5I_HSTIMER
+
+config MACH_SUN7I
+	bool "Allwinner A20 (sun7i) SoCs support"
+	default ARCH_SUNXI
+	select ARM_GIC
+	select ARM_PSCI
+	select HAVE_ARM_ARCH_TIMER
 	select SUN5I_HSTIMER
+
+endif