scsi: ufs-qcom-ice: add null pointer check

ufs_qcom_ice_req_setup() function might access the uninitialized pointers,
this change makes sure that there are no null pointer accesses.

Change-Id: I83c3e2f015a474d5eba6ddaeeaa860e79717760f
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>