V4L/DVB (6124): cx25840: add a few 10 microsecond delays

There were a couple of places in the cx25840 initialization where the
datasheet called for a 10 microsecond delay, which we ignored because
of the 10 usec I2C delay. Put them in anyway now that the I2C delay
was decreased to 5 usec.

Signed-off-by: Tyler Trafford <ttrafford@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>