OMAP3 Move twl4030 mmc function

Because twl4030 now has its own device files, move and rename
twl4030_mmc_config.

twl4030_mmc_config initializes the twl4030 power setting to
the mmc device.  Because it is in the twl4030 power domain, move
it out of drivers/mmc/omap3_mmc.c and into drivers/power/twl4030.c.

The function was renamed to twl4030_power_mmc_init because all
the functions in this file are to have the format

twl4030_power_<device>_<action>

In this case the suffix is mmc_init so
device : mmc
action : init

Signed-off-by: Tom Rix <Tom.Rix@windriver.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Heiko Schocher <hs@denx.de>