V4L/DVB: tm6000: bugfix reading problems with demodulator zl10353

Reading from zl10353 with tm6000 has a bug. For example:

regs  w/o patch  with patch

0x06     0x00        0x7f
0x07     0x33        0x30
0x08     0x00        0x00
0x09     0x58        0x50
0x0f     0x31        0x28
0x10     0x00        0x84

This patch provides the workaround for the bug

[mchehab@redhat.com: Fix merge conflict and add a comment at the workaround]
Signed-off-by: Stefan Ringel <stefan.ringel@arcor.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>