ARM: OMAP3: Initialize more devices for LDP

Based on an earlier patches by Stanley.Miao <stanley.miao@windriver.com>
and Nishant Kamat <nskamat@ti.com>.

Note that at the ads7846 support still needs support for vaux_control
for the touchscreen to work.

Signed-off-by: Tony Lindgren <tony@atomide.com>