V4L/DVB (13575): em28xx: Use the complete address/command RC5 code for WinTV USB2

This device uses an i2c chip to retrieve the keycode from a RC5 remote.
Instead of just getting 6 bits, improve the routine to get 11 bits.

This means that the complete RC5 table for Hauppauge Grey IR can be used
with this device.

Unfortunately, it seems that this IR receiver is not capable of getting
the full 14 (or 13 bits) from the RC5 protocol.

At lest now, with the new code, it is possible to replace this IR table
by another RC5 table.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>