scsi: ufs: fix issue with clock gating

In a case where clocks are gated and to ungate them ufshcd_hold()
is called with async flag set to false, clocks would be enabled
within the same context. There is a bug in the current code where
the active_reqs counter is getting incremented twice. This would
further prevent clock gating from happening.  Fix this issue by
updating the active_reqs correctly.

Change-Id: I70bdae8d1ccc189db9bd2e9fee66678c571933f6
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>