gpio: mxs: GPIO_MXS should not default to y unconditionally

Merely enabling CONFIG_COMPILE_TEST should not enable additional code.
To fix this, restrict the automatic enabling of GPIO_MXS to ARCH_MXS,
and ask the user in case of compile-testing.

Fixes: 6876ca3 ("gpio: mxs: add COMPILE_TEST support for GPIO_MXS")
Cc: <stable@vger.kernel.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

drivers/gpio/Kconfig

@@ -441,8 +441,9 @@ config GPIO_MXC
 	select GENERIC_IRQ_CHIP
 
 config GPIO_MXS
-	def_bool y
+	bool "Freescale MXS GPIO support" if COMPILE_TEST
 	depends on ARCH_MXS || COMPILE_TEST
+	default y if ARCH_MXS
 	select GPIO_GENERIC
 	select GENERIC_IRQ_CHIP