omap3: update Pandora defconfig

This patch updates defconfig to enable options needed to properly
boot OMAP3 pandora board. It also enables MMC, OTG, GPIO LEDs,
TWL4030 GPIO and sound drivers.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>