omap2: fix assorted compiler warnings

This patch fixes these compiler warnings:

  CC      arch/arm/mach-omap2/mux.o
arch/arm/mach-omap2/mux.c: In function 'omap_mux_init_gpio':
arch/arm/mach-omap2/mux.c:90: warning: 'gpio_mux' may be used uninitial
ized in this function

  CC      arch/arm/plat-omap/gpio.o
arch/arm/plat-omap/gpio.c: In function 'omap2_gpio_resume_after_idle':
arch/arm/plat-omap/gpio.c:2152: warning: 'l' may be used uninitialized
in this function
arch/arm/plat-omap/gpio.c: In function 'omap2_gpio_prepare_for_idle':
arch/arm/plat-omap/gpio.c:2085: warning: 'l2' may be used uninitialized
in this function
arch/arm/plat-omap/gpio.c:2085: warning: 'l1' may be used uninitialized
in this function

  CC      arch/arm/mach-omap2/board-omap4panda.o
arch/arm/mach-omap2/board-omap4panda.c: In function 'omap4_panda_init':
arch/arm/mach-omap2/board-omap4panda.c:277: warning: unused variable 's
tatus'

Signed-off-by: Sanjeev Premi <premi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>