V4L/DVB (9442): Revert back previous change to 90MHz

Note:
* At High Symbol Rates we do not have enouph machine cycles to handle the
  incoming symbols and hence might run into problems at the very end of the
  specified definition
* Most of the equations have been calculated for a master clock of 99 MHz,
  running at 90MHz, raises lot of issues such as the need to recalculate
  all of them , which is eventually very painful.

Signed-off-by: Manu Abraham <manu@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>