omap: Stalker board: switch over to gpio_set_debounce

omap: Stalker board: switch over to gpio_set_debounce

With latest linus's tip, omap3_defconfig is broken.

 LD      init/built-in.o
  LD      .tmp_vmlinux1
arch/arm/mach-omap2/built-in.o: In function `ads7846_dev_init':
linux-2.6/arch/arm/mach-omap2/board-omap3stalker.c:542: undefined reference to `omap_set_gpio_debounce'
linux-2.6/arch/arm/mach-omap2/board-omap3stalker.c:543: undefined reference to `omap_set_gpio_debounce_time'
make: *** [.tmp_vmlinux1] Error 1

>From the commit 48feb337475a ( arm: omap: switch over to gpio_set_debounce),
board-omap3stalker.c seems to be missed out or got merged later.
The patch was to remove omap-specific implementations for gpio debouncing
in favor of gpiolib function.

Cc: Felipe Balbi <felipe.balbi@nokia.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>