OMAP2+: mux: fix compilation warnings

Fix below compilation warnings.

arch/arm/mach-omap2/omap_hwmod.c: In function 'omap_hwmod_for_each':
arch/arm/mach-omap2/omap_hwmod.c:1631: warning: 'ret' may be used uninitialized in this function

arch/arm/mach-omap2/mux.c: In function 'omap_mux_get_gpio':
arch/arm/mach-omap2/mux.c:917: warning: 'm' may be used uninitialized in this function

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/mux.c

@@ -906,7 +906,7 @@ static struct omap_mux *omap_mux_get_by_gpio(
 u16 omap_mux_get_gpio(int gpio)
 {
 	struct omap_mux_partition *partition;
-	struct omap_mux *m;
+	struct omap_mux *m = NULL;
 
 	list_for_each_entry(partition, &mux_partitions, node) {
 		m = omap_mux_get_by_gpio(partition, gpio);

arch/arm/mach-omap2/omap_hwmod.c

@@ -1628,7 +1628,7 @@ int omap_hwmod_for_each(int (*fn)(struct omap_hwmod *oh, void *data),
 			void *data)
 {
 	struct omap_hwmod *temp_oh;
-	int ret;
+	int ret = 0;
 
 	if (!fn)
 		return -EINVAL;