omap4 hsmmc: Register offset handling

In OMAP4, as per new PM programming model, the legacy registers
which were there in OMAP3 are all shifted by 0x100 while new one's
are added from offset 0 to 0x10.
For OMAP4, the register offset appending of 0x100 done in devices.c
currently, is moved to driver file.This change fits in for current
implementation as well as once the driver undergoes hwmod adaptation.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Adrian Hunter <adrian.hunter@nokia.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Signed-off-by: Kishore Kadiyala <kishore.kadiyala@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>