media: venus: venc: Clamp param smaller than 1fps and bigger than 240

The driver uses "whole" fps in all its calculations (e.g. in
load_per_instance()). Those calculation expect an fps bigger than 1, and
not big enough to overflow.

Clamp the param if the user provides a value that will result in an invalid
fps.

Reported-by: Hans Verkuil <hverkuil@xs4all.nl>
Closes: https://lore.kernel.org/linux-media/f11653a7-bc49-48cd-9cdb-1659147453e4@xs4all.nl/T/#m91cd962ac942834654f94c92206e2f85ff7d97f0


Fixes: aaaa93ed ("[media] media: venus: venc: add video encoder files")
Cc: stable@vger.kernel.org
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
[bod: Change "parm" to "param"]
Signed-off-by: Bryan O'Donoghue <bod@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>