staging: vc04_service: codec: Allow start_streaming to update the buffernum

staging: vc04_service: codec: Allow start_streaming to update the buffernum

start_streaming passes a count of how many buffers have been queued
to videobuf2.

Allow this value to update the number of buffers the VPU allocates
on a port to avoid buffer recycling issues.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
[sw0312.kim: cherry-pick rpi-5.4.y commit to fix video decoding seek issue]
Ref: https://github.com/raspberrypi/linux/pull/3790
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Change-Id: Iaf37f57df95789cc8987b268feab1f0fa7377849