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>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 37c4bd1..d0c4118 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -87,6 +87,7 @@
 
 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.