gpio: ath79: Allow building in compile tests

To allow building the driver in compile tests we must drop the
dependency on asm/mach-ath79/ar71xx_regs.h. For this we replace the
include with local definition of the registers needed for this driver.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 020a44a..3c1bb91 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -129,7 +129,7 @@
 config GPIO_ATH79
 	tristate "Atheros AR71XX/AR724X/AR913X GPIO support"
 	default y if ATH79
-	depends on ATH79
+	depends on ATH79 || COMPILE_TEST
 	select GPIO_GENERIC
 	help
 	  Select this option to enable GPIO driver for