media: cx23885: change 887/888 default to 888

Proper cx2388x chip type is detected in cx25840 probe, the clock
rate is untouched however in probe. The cx25840 only checks for
non default clock values for 888 and provides custom settings for
25MHz 888. This change ensures that cx23888 chips with default 50MHz
crystals will not get configured as if they have 25MHz crystals. A
cx23887 board will continue to be configured for 25MHz crystal as
there is no custom clock support included for it.

Signed-off-by: Brad Love <brad@nextdimension.cc>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>