media: allegro: fix calculation of CPB size

The cpb_size is given in kilobytes, but the bitrate is given in bits per
second. Therefore, the calculation of the initial removal delay and the
cpb size for the firmware were wrong.

Convert the bitrate to kilobytes before calculating the cpb size in 90
kHz units for sending it to the firmware. Also reuse the result for the
initial removal delay, to make it obvious that we are setting the
initial removal delay to the maximum value.

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>