mmc-omap: Add support for 16-bit and 32-bit registers

The omap850 and omap730 use 16-bit registers instead of 32-bit, requiring
a modification of the register addresses in the mmc-omap driver.  To resolve
this, a bit shift is performed on base register addresses, either by 1 or 2
bits depending on the CPU in use.  This yields the correct registers for
each CPU.

Signed-off-by: Marek Belisko <marek.belisko@open-nandra.com>
Signed-off-by: Cory Maccarrone <darkstar6262@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>