r600/sfn: extend life range of all variables by one

This is a strange fix for some gles 3.1 tests with atomics. Maybed
the register holding the atomic add value can't be re-used in the
first instruction after an GDS instruction.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6925>

src/gallium/drivers/r600/sfn/sfn_liverange.cpp

@@ -358,6 +358,11 @@ register_live_range temp_access::get_required_live_range()
          break;
    }
    result.is_array_elm = is_array_element;
+
+   /* This fixes a few tests, but it is not clear why. */
+   if (result.end != result.begin)
+      ++result.end;
+
    return result;
 }