[media] s5p-mfc: Add QP setting support for vp8 encoder

Adds v4l2 controls to set MIN, MAX QP values and
I, P frame QP for vp8 encoder.

Signed-off-by: Kiran AVND <avnd.kiran@samsung.com>
Signed-off-by: Arun Kumar K <arun.kk@samsung.com>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>