[media] s5p-mfc: Add init buffer cmd to MFCV6

Latest MFC v6 firmware requires tile mode and loop filter
setting to be done as part of Init buffer command, in sync
with v7. This patch adds this support for new v6 firmware.

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