msm: vidc: update max P frames num for encode

Remove the restriction on the max number of
P frame interval.

Change-Id: I637372d7b0d409602df251bad4a135b25514dc95
Signed-off-by: Arun Menon <avmenon@codeaurora.org>
Signed-off-by: houst0nn <houstonn@gmail.com>