scsi: ufs: optimize clock gate work

In a case where gate work is called as part of cancel work from ungate
path the clk state would be marked as REQ_CLKS_ON.  There is no point
gating the clocks and then end up turning them ON immediately in ungate
work, save time by skipping the gate work and change the clk state to
CLKS_ON as they are not turned off yet.

Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>