gpio: Use __devexit at necessary places

The function gen_74x164_remove and mc33880_remove are used only wrapped
by __devexit_p so define it using __devexit.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/gpio/mc33880.c b/drivers/gpio/mc33880.c
index 935479d..00f6d24 100644
--- a/drivers/gpio/mc33880.c
+++ b/drivers/gpio/mc33880.c
@@ -146,7 +146,7 @@
 	return ret;
 }
 
-static int mc33880_remove(struct spi_device *spi)
+static int __devexit mc33880_remove(struct spi_device *spi)
 {
 	struct mc33880 *mc;
 	int ret;