scsi: ufs: debugfs: add option to read local DME attribute

This patch adds the debugfs capability to read the DME attribute of
local UniPro/M-PHY. This should help for debugging.

Change-Id: I2dea471f6bcf591a69206e127d3c9e3febbbc68f
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>