mmc: omap_hsmmc: fix module re-insertion

OMAP4 and OMAP3 HSMMC IP registers differ by 0x100 offset.
Adding the offset to platform_device resource structure
increments the start address for every insmod operation.
MMC command fails on re-insertion as module due to incorrect register
base.  Fix this by updating the ioremap base address only.

Signed-off-by: Balaji T K <balajitk@ti.com>
Signed-off-by: Venkatraman S <svenkatr@ti.com>
Signed-off-by: Chris Ball <cjb@laptop.org>