msm: camera: reqmgr: Skip reset if no request from UMD

In case of slot is marked as skip idx it will
apply the request and try to reset a previous slot
which might have the request for which we have got a
bubble. To make sure this does not happen, reset a
slot only when the request is valid request and
not the last applied request.

Change-Id: I03a542baffcd332e030d352df5ce19f4dbcc0dd6
Signed-off-by: Tejas Prajapati <tpraja@codeaurora.org>