Add some additional H.264 attributes, "max-smbps" and "max-fps", for passthrough.

(closes issue ASTERISK-20206)
Reported by: ddkprog
Patches:
     res_format_attr_h264.c.diff uploaded by ddkprog (license 6008)
........

Merged revisions 371426 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@371427 65c4cc65-6c06-0410-ace0-fbb531ad65f3