ARM: OMAP: hsmmc: Support for AM3517 MMC1 voltages

This patch fixes the following error message which appears
while intializing MMC1 on the AM3517 EVM base-board:
    mmc0: host doesn't support card's voltages
    mmc0: error -22 whilst initialising SD card
The ocr_mask, which enumerates the volatges supported by the
MMC card was not being indicated before, assuming that a separate
Vcc regulator maybe another controllable regulator driver would be
doing this. This patch statically specifies a subset of the voltages
supported by the MMC driver, which are provided by the current fixed
voltage regulator on AM3517 EVM.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Abhilash K V <abhilash.kv@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>