V4L/DVB (5936): tda10023: Remove range check of symbol rate

Remove incorrect range check of symbol rate, spotted by the coverity 
checker and reported by Adrian Bunk.

These range checks are performed by dvb_core now.

Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>