support built-in functions "mul24", "mad24"
support built-in functions "mul24", "mad24"

Signed-off-by: Homer Hsing <f17cb7083eb6a94c3fb9d8f09ceefa518f721ab2@intel.com>
Reviewed-by: He Junyan <8f73a735c668918c9613b750d3a88ebf2489599f@inbox.com>

freedesktop-unofficial-mirror/beignet,freedesktop-unofficial-mirror/beignet,ignatenkobrain/beignet,freedesktop-unofficial-mirror/beignet,ignatenkobrain/beignet,ignatenkobrain/beignet,zhenyw/beignet,wdv4758h/beignet,wdv4758h/beignet,zhenyw/beignet,ignatenkobrain/beignet,freedesktop-unofficial-mirror/beignet,wdv4758h/beignet,zhenyw/beignet,wdv4758h/beignet,wdv4758h/beignet,ignatenkobrain/beignet,zhenyw/beignet,zhenyw/beignet