V4L/DVB: tm6000: fix i2c read

Set correct limit for I2C packet.
Use different method for the tm5600/tm6000 and tm6010 to read word.

[mchehab@redhat.com: Fix CodingStyle]
Signed-off-by: Beholder Intl. Ltd. Dmitry Belimov <d.belimov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>