mmc: msm_sdcc: Update hw_reset functionality for resetting SD card

Some targets whose regulators are controlled through platform-data in
the board files. Add support for such SDC slots to enable hw_reset
functionality

Change-Id: I5033cd96f8816008ee7fa546bd81d83a33373299
Signed-off-by: Pratibhasagar V <pratibha@codeaurora.org>