libcgc: Add SLE instruction

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
libcgc: Add saturate output-modifier

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
libcgc: Add scalar MOV instruction

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
libcgc: Only write varying if bit 126 is set

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
libcgc: Write predicate register if bit 125 is set

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
libcgc: Support predicate operations