The currently used functions for converting the transmission mode and guard
interval from the internal values to the DVBv5 API values do not return
correct values for ISDB broadcasts:

- The raw (debugfs) transmission mode is an integer whose values can be
1, 2 or 3, that corresponds to 2K, 4K and 8K FFT modes respectively.
However sms_to_mode() expects values 2, 4 or 8.
- Guard interval, as defined by smscoreapi.h returns "1 divided by value"
instead of 0, 1, 2, and 3 as defined in sms_to_guard_interval_table().

This commit implements ISDB-T specific methods for converting the internal
values for the aforementioned parameters to the DVBv5 API values. It also
adds support for reporting FEC and time interleaving values for each one
of the layers.

[mchehab: fix two coding style whitespace warnings]
Link: https://lore.kernel.org/linux-media/20201222030522.28774-1-nicolasstuardodiaz@gmail.comSigned-off-by: Nicolas Stuardo Diaz <nicolasstuardodiaz@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>