r600: revert disabling llvm draw

Now that llvm supports NIR and lowers uniforms to UBO in draw
calls when this hasn't be done before this can be used again.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6706>
diff --git a/src/gallium/drivers/r600/r600_pipe_common.c b/src/gallium/drivers/r600/r600_pipe_common.c
index 8fa9aa8..8965f27 100644
--- a/src/gallium/drivers/r600/r600_pipe_common.c
+++ b/src/gallium/drivers/r600/r600_pipe_common.c
@@ -1286,10 +1286,6 @@
 	rscreen->family = rscreen->info.family;
 	rscreen->chip_class = rscreen->info.chip_class;
 	rscreen->debug_flags |= debug_get_flags_option("R600_DEBUG", common_debug_options, 0);
-	int has_draw_use_llvm = debug_get_bool_option("DRAW_USE_LLVM", FALSE);
-	if (!has_draw_use_llvm)
-	   setenv("DRAW_USE_LLVM", "no", 0);
-
 
 	r600_disk_cache_create(rscreen);