drivers/gpio: Fix drivers who are implicit users of module.h

A pending cleanup will mean that module.h won't be implicitly
everywhere anymore.  Make sure the modular drivers in gpio
are actually calling out for <module.h> explicitly in advance.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/gpio/gpio-74x164.c

@@ -15,6 +15,7 @@
 #include <linux/spi/74x164.h>
 #include <linux/gpio.h>
 #include <linux/slab.h>
+#include <linux/module.h>
 
 struct gen_74x164_chip {
 	struct spi_device	*spi;