gpio/it8761e: Restrict it8761e gpio driver to x86.

This driver does an unconditional read of io space during module init which
causes a bad dereference on ARM.  It looks to me like this is an x86 only
drivers, so restrict it to only compile on x86.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Denis Turischev <denis@compulab.co.il>

drivers/gpio/Kconfig

@@ -87,6 +87,7 @@ config GPIO_GENERIC_PLATFORM
 
 config GPIO_IT8761E
 	tristate "IT8761E GPIO support"
+	depends on X86  # unconditional access to IO space.
 	help
 	  Say yes here to support GPIO functionality of IT8761E super I/O chip.