mips: ar7: include linux/gpio/driver.h

The change to remove the implicit gpio/driver.h include was done
after fixing all the other users, but the ar7 file still needs
the same change.
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Fixes: 21d9526d ("gpiolib: Make the legacy <linux/gpio.h> consumer-only")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

arch/mips/ar7/gpio.c

@@ -7,7 +7,7 @@
 
 #include <linux/init.h>
 #include <linux/export.h>
-#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
 
 #include <asm/mach-ar7/ar7.h>