sh: mach-sdk7786: Add support for fpga gpios.

The sdk7786 FPGA supports a number of user settable input switches that
are otherwise unused. This wires up a dummy gpio chip for the switch bank
to simply expose them to userspace.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/boards/Kconfig b/arch/sh/boards/Kconfig
index 90ed1ec..bb2cb27 100644
--- a/arch/sh/boards/Kconfig
+++ b/arch/sh/boards/Kconfig
@@ -155,6 +155,7 @@
 	depends on CPU_SUBTYPE_SH7786
 	select SYS_SUPPORTS_PCI
 	select NO_IOPORT if !PCI
+	select ARCH_WANT_OPTIONAL_GPIOLIB
 	help
 	  Select SDK7786 if configuring for a Renesas Technology Europe
 	  SH7786-65nm board.