radeonsi: remove bogus r600-- triple

As mentioned by Michel Dänzer for LLVM >= 3.6 we create the
LLVMTargetMachine (with triple amdgcn--), as we setup the radeonsi
context. For older LLVM or hardware (r600) the triple is always r600--
and is created at a later stage - radeon_llvm_compile()

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>

src/gallium/drivers/radeonsi/si_pipe.c

@@ -85,8 +85,6 @@ static struct pipe_context *si_create_context(struct pipe_screen *screen, void *
 	LLVMTargetRef r600_target;
 #if HAVE_LLVM >= 0x0306
 	const char *triple = "amdgcn--";
-#else
-	const char *triple = "r600--";
 #endif
 	int shader, i;