brw: consider LOAD_PAYLOAD fully defined

It's mostly used for SEND messages and fully defines the register data
(that's its purpose after all).

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36457>

src/intel/compiler/brw_analysis_def.cpp

@@ -86,6 +86,7 @@ brw_def_analysis::update_for_reads(const brw_idom_tree &idom,
        * destination may have multiple dynamic assignments.
        */
       if (inst->opcode != SHADER_OPCODE_LOAD_REG &&
+          inst->opcode != SHADER_OPCODE_LOAD_PAYLOAD &&
           !def_insts[nr] && inst->dst.file == VGRF)
          mark_invalid(inst->dst.nr);
    }