[media] em28xx: support for Hauppauge WinTV-dualHD 01595 ATSC/QAM

Hauppauge WinTV-dualHD model 01595 is a USB 2.0 dual ATSC/QAM tuner with
the following components:

USB bridge: Empia em28274
Demodulator: 2x LG LGDT3306a at addresses 0xb2 and 0x1c
Tuner: 2x Silicon Labs si2157 at addresses 0xc0 and 0xc4

This patch enables only the first tuner.

Signed-off-by: Kevin Cheng <kcheng@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>