GPIO_RDC321X: select MFD_SUPPORT to squelch kconfig warning

Fix kconfig dependency warning to satisfy dependencies:

warning: (GPIO_RDC321X && PCI && GPIOLIB) selects MFD_RDC321X which has unmet direct dependencies (MFD_SUPPORT && PCI)
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpio/Kconfig

@@ -342,6 +342,7 @@ config GPIO_TIMBERDALE
 config GPIO_RDC321X
 	tristate "RDC R-321x GPIO support"
 	depends on PCI && GPIOLIB
+	select MFD_SUPPORT
 	select MFD_CORE
 	select MFD_RDC321X
 	help