gpio: Kconfig: drop unknown symbol 'CS5535_GPIO'

Commit af0c25c4 ("staging: remove obsoleted CS5535/CS5536 GPIO
driver") dropped CS5535_GPIO. So this last reference to CS5535_GPIO has
been an (inconsequential) nop since v3.1. Drop it too.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/gpio/Kconfig

@@ -356,7 +356,7 @@ comment "PCI GPIO expanders:"
 
 config GPIO_CS5535
 	tristate "AMD CS5535/CS5536 GPIO support"
-	depends on PCI && X86 && !CS5535_GPIO && MFD_CS5535
+	depends on PCI && X86 && MFD_CS5535
 	help
 	  The AMD CS5535 and CS5536 southbridges support 28 GPIO pins that
 	  can be used for quite a number of things.  The CS5535/6 is found on