media: venus: venc_ctrls: Change default header mode

It is observed that on Venus v1 the default header-mode is producing
a bitstream which is not playble. Change the default header-mode to
joined with 1st frame.

Fixes: 002c22bd ("media: venus: venc: set inband mode property to FW.")
Cc: stable@vger.kernel.org # v5.12
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>