intel/gen_decoder: Fix length for Media State/Object commands
intel/gen_decoder: Fix length for Media State/Object commands

From BDW PRM, Volume 6: Command Stream Programming, 'Render Command
Header Format'.

Signed-off-by: Jordan Justen <a79006884ba9cf5f4f7fcbb92a15b208780d8c97@intel.com>
Reviewed-by: Lionel Landwerlin <9463032a5b99ffad10f36631678a833369a311b5@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler