lima/ppir: initialize slots array for dummy/undef

Some functions in ppir iterate the ppir_op_info slots arrays looking
for the PPIR_INSTR_SLOT_END token. The dummy/undef internal ops may
appear in the scheduling code and their slots arrays did not contain
that token, which could result in invalid array reads.
Reported by gcc -fsanitize=address.

Signed-off-by: Erico Nunes <nunes.erico@gmail.com>
Reviewed-by: Vasily Khoruzhick <anarsoul@gmail.com>
Cc: 22.0 <mesa-stable>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14894>

src/gallium/drivers/lima/ir/pp/node.c

@@ -333,12 +333,14 @@ const ppir_op_info ppir_op_infos[] = {
       .name = "undef",
       .type = ppir_node_type_alu,
       .slots = (int []) {
+         PPIR_INSTR_SLOT_END
       },
    },
    [ppir_op_dummy] = {
       .name = "dummy",
       .type = ppir_node_type_alu,
       .slots = (int []) {
+         PPIR_INSTR_SLOT_END
       },
    },
 };