V4L/DVB (3382): Fix stv0297 for qam128 on tt c1500 (saa7146)

I have a TT C1500 card (saa7146, STV0297) which had problems tuning
channels at QAM128 (like the ones in the Finnish HTV / Welho network).
A fix which seems to work perfectly so far is to change the delay for
QAM128 to the same values as for QAM256 in stv0297_set_frontend(),

Signed-off-by: Mattias Nordstrom <nordstrom@realnode.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>