shader_bytecode: Add Control Code enum 0xf

Control Code 0xf means to unconditionally execute the instruction. This
value is passed to most BRA, EXIT and SYNC instructions (among others)
but this may not always be the case.

src/video_core/engines/shader_bytecode.h

@@ -267,7 +267,7 @@ enum class ControlCode : u64 {
     GTU = 12,
     NEU = 13,
     GEU = 14,
-    //
+    T = 15,
     OFF = 16,
     LO = 17,
     SFF = 18,