[ffmpeg/el8] (32 commits) ...Make it build for el8

Summary of changes: 7d10e2b... Rework build dependencies for cuda (*) b2016c1... Fixup rpi br (*) b1a2e6b... Add omx/omx_rpi support (*) e747115... Add omx/omx_rpi support (*) 5dbf755... Drop opencv by default (*) 0772860... Update changelog (*) d30cc00... Update RHEL case (*) 7f173da... Enable libssh support by default (rfbz#5135) (*) 73c7691... Update to 4.1.1 release (*) e6ba26a... Rebuild for new x265 (*) 3037a6b... - Rebuilt for https://fedoraproject.org/wiki/Fedora_30_Mass (*) 5b6887b... Mass rebuild for x264 (*) 8f13676... Update to 4.1.2 release (*) eae0340... Update to 4.1.3 release (*) cd3bdd1... Backport upstream patch (*) 23cc013... Update changelog (*) 1670f1d... Bump to latest cuda (*) d72b341... Only el7 and el8 will be tested, el8 still wip (*) 06e40d4... Rebuilt (*) 447488b... Update to 4.1.4 release (*) 6045963... Add patch for gnutls set_default_priority (*) af22713... Update changelog (*) 9737b15... Revert to the patch for 4.1x/4.0x (*) a5ff938... Drop subversion (*) 70ce5a1... Update to 4.2 release (*) fccd52f... clean up (*) 98589f0... Patch1 merged upstream (*) 4e6e648... Add patch to fix ppc build (*) 355bbbf... Add version for Br dav1d (*) f806fb0... - Rebuilt for https://fedoraproject.org/wiki/Fedora_31_Mass (*) dfe4396... Rebuild for dav1d and aom SONAME bump (*) 60eebee... Make it build for el8 (*) (*) This commit already existed in another branch; no separate mail sent