media: allegro: increase offset in CAPTURE buffer

The HEVC Non-VCL NAL units require more space than the H.264 Non-VCL NAL
units. Therefore, the driver needs to reserve more space in front of the
actual coded data that is written by the hardware codec.

Increase the offset that shall be used by the hardware codec from 64
bytes to 128 bytes which is as arbitrary as before.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>