blackfin: force use of gpiolib

Set the GENERIC_GPIO option to false by default and force the use of
gpiolib instead of making it optional, to prepare for the removal of
GENERIC_GPIO.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Steven Miao <realmz6@gmail.com>

arch/blackfin/Kconfig

@@ -31,7 +31,7 @@ config BLACKFIN
 	select HAVE_OPROFILE
 	select HAVE_PERF_EVENTS
 	select ARCH_HAVE_CUSTOM_GPIO_H
-	select ARCH_WANT_OPTIONAL_GPIOLIB
+	select ARCH_REQUIRE_GPIOLIB
 	select HAVE_UID16
 	select VIRT_TO_BUS
 	select ARCH_WANT_IPC_PARSE_VERSION
@@ -56,7 +56,7 @@ config ZONE_DMA
 	def_bool y
 
 config GENERIC_GPIO
-	def_bool y
+	def_bool n
 
 config FORCE_MAX_ZONEORDER
 	int