agx: Add AGX_MESA_DEBUG=noopt option

To disable the optimizer. Trying to root cause a Neverball bug, this
gives one less thing to worry.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17198>

src/asahi/compiler/agx_compiler.h

@@ -45,6 +45,7 @@ enum agx_dbg {
    AGX_DBG_VERBOSE     = BITFIELD_BIT(3),
    AGX_DBG_INTERNAL    = BITFIELD_BIT(4),
    AGX_DBG_NOVALIDATE  = BITFIELD_BIT(5),
+   AGX_DBG_NOOPT       = BITFIELD_BIT(6),
 };
 
 extern int agx_debug;