sunxi: Add SUN6I_PRCM kconfig entry

Add simple and meaningful kconfig option for prcm.c
instead of using MACH type on Makefile.

PRCM (Power/Reset/Clock Management) is considered as a
Multi-Functional Device, so used the same on Kconfig definition.
Signed-off-by: NJagan Teki <jagan@amarulasolutions.com>
Acked-by: NMaxime Ripard <maxime.ripard@bootlin.com>

arch/arm/mach-sunxi/Kconfig

@@ -6,6 +6,12 @@ config SPL_LDSCRIPT
 config IDENT_STRING
 	default " Allwinner Technology"
 
+config SUN6I_PRCM
+	bool
+	help
+	  Support for the PRCM (Power/Reset/Clock Management) unit available
+	  in A31 SoC.
+
 config SUNXI_HIGH_SRAM
 	bool
 	default n
@@ -88,6 +94,7 @@ config MACH_SUN6I
 	select CPU_V7_HAS_NONSEC
 	select CPU_V7_HAS_VIRT
 	select ARCH_SUPPORT_PSCI
+	select SUN6I_PRCM
 	select SUNXI_GEN_SUN6I
 	select SUPPORT_SPL
 	select ARMV7_BOOT_SEC_DEFAULT if OLD_SUNXI_KERNEL_COMPAT

arch/arm/mach-sunxi/Makefile

@@ -16,7 +16,7 @@ obj-y	+= pinmux.o
 ifndef CONFIG_MACH_SUN9I
 obj-y	+= usb_phy.o
 endif
-obj-$(CONFIG_MACH_SUN6I)	+= prcm.o
+obj-$(CONFIG_SUN6I_PRCM)	+= prcm.o
 obj-$(CONFIG_MACH_SUN8I)	+= prcm.o
 obj-$(CONFIG_MACH_SUN9I)	+= prcm.o
 obj-$(CONFIG_MACH_SUN6I)	+= p2wi.o