gallivm: set correct opcode info from unary/binary/ternary emits
gallivm: set correct opcode info from unary/binary/ternary emits

and clear the emit_data structure.

The new radeonsi min/max opcode implementation requires this.

(it looks good according to Roland S.)

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler