msm: vidc: skip fps round off when client sets 1 fps

sometimes fps is rounded off one lesser, makes it
to zero, when the client is setting fps as 1.
This exposes division by zero crash when calculating
the load for non realtime usescases. Crash is observed
in recent monkey runs.

Change-Id: I4ec824d658ed3a14ab43ca031e989b01adfddc11
CRs-Fixed: 933641
Signed-off-by: Balamurugan Alagarsamy <balaga@codeaurora.org>