firmware v1.2 handler

Currently, dvb_usb_dib0700_ir_proto is supported only with firmwares
older than 1.2. Adds support for it also with the newer firmware.

This is needed in order to support PixelView SBTVD IR.

Cc: Patrick Boettcher <pb@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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