scsi: ufs: creates wrapper functions for vops

In order to simplify the code a set of wrapper functions is created
to test and call each of the variant operations.

Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Reviewed-by: Gilad Broner <gbroner@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
Tested-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>