Constant IP-ID: for inner IP header, fix case with NBO=0/SID=0/RND=0 on PowerPC, ie. big endian.
Constant IP-ID: for inner IP header, fix case with NBO=0/SID=0/RND=0 on PowerPC, ie. big endian.

didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc