media: rkisp1: isp: Merge ISP_ACQ_PROP configuration in single variable

The rkisp1_config_isp() function stores the value of the input selection
and polarity configuration in two different local variables, OR'ed
together when writing the register. Merge them into a single acq_prop
variable.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Dafna Hirschfeld <dafna@fastmail.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>