scsi: ufs: perform full reset at initialization

The phy initialization sequence assumes a POR state but
the bootloaders can leave PHY at an already initialized
state, hence there could potentially be issues with the
initialization from ufs driver. Perform a full reset to
start from a power on reset state. Also a reset is
required by the UFS hardware programming guide.

Change-Id: I0118b0d3013166aeec0bb0bc0ef181e48998e758
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>