Document the following properties for controlling an ATSC-MH frontend:

DTV_ATSCMH_FIC_VER - Version number of the FIC signaling data
DTV_ATSCMH_PARADE_ID - Parade identification number
DTV_ATSCMH_NOG - Number of MH groups per MH subframe for a designated parade
DTV_ATSCMH_TNOG - Total number of MH groups in all parades in one subframe
DTV_ATSCMH_SGN - Start group number
DTV_ATSCMH_PRC - Parade repetition cycle
DTV_ATSCMH_RS_FRAME_MODE - RS frame mode
DTV_ATSCMH_RS_FRAME_ENSEMBLE - RS frame ensemble
DTV_ATSCMH_RS_CODE_MODE_PRI - RS code mode (primary)
DTV_ATSCMH_RS_CODE_MODE_SEC - RS code mode (secondary)
DTV_ATSCMH_SCCC_BLOCK_MODE - Series Concatenated Convolutional Code Block Mode
DTV_ATSCMH_SCCC_CODE_MODE_A - Series Concatenated Convolutional Code Rate A
DTV_ATSCMH_SCCC_CODE_MODE_B - Series Concatenated Convolutional Code Rate B
DTV_ATSCMH_SCCC_CODE_MODE_C - Series Concatenated Convolutional Code Rate C
DTV_ATSCMH_SCCC_CODE_MODE_D - Series Concatenated Convolutional Code Rate D
DTV_ATSCMH_FIC_ERR - FIC error count
DTV_ATSCMH_CRC_ERR - CRC error count
DTV_ATSCMH_RS_ERR - RS error count
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>