[*] StbMainApp: Improve using dvb_isLinuxTuner(). It allways true for non STSDK boards.

Signed-off-by: Anton Sergeev <Anton.Sergeev@elecard.ru>
[+] StbMainApp: Add support for ATSC tuners.

Signed-off-by: Anton Sergeev <Anton.Sergeev@elecard.ru>