scsi: ufs: Fix compilation error in ufs cmd logging

In function ufshcd_add_cmd_trace(), cmd_id entry is
not initialized when CONFIG_SCSI_UFSHCD_CMD_LOGGING
is disabled and resulting in compilation errors.This
change initializes cmd_id to fix compilation error.

Change-Id: I1b89f4bf93432dab81b1b76736ac003099572b22
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>