ARM: shmobile: Select GPIO in case of the r7s72100 SoC

The r7s72100 contains GPIO controllers so make sure the GPIO
subsystem can be built by selecting ARCH_WANT_OPTIONAL_GPIOLIB.
Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/Kconfig

@@ -111,6 +111,7 @@ config ARCH_EMEV2
 
 config ARCH_R7S72100
 	bool "RZ/A1H (R7S72100)"
+	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARM_GIC
 	select CPU_V7
 	select SH_CLK_CPG