[aapcs64] Fix reference to num_za_save_slices

Author: nsz-arm

aapcs64/aapcs64.rst

@@ -1439,7 +1439,7 @@ The following table summarizes the three ZA states:
 +-------------------------+-----------------+--------+------------------------+-------------+
 | ``za_save_buffer``      |            null |    N/A |                nonnull | [#za-vars]_ |
 +-------------------------+-----------------+--------+------------------------+-------------+
-| ``num_za_save_buffers`` |               0 |    N/A |                nonzero | [#za-vars]_ |
+| ``num_za_save_slices``  |               0 |    N/A |                nonzero | [#za-vars]_ |
 +-------------------------+-----------------+--------+------------------------+-------------+
 | ZA_LIVE                 |               0 |    all | ``num_za_save_slices`` |             |
 +-------------------------+-----------------+--------+------------------------+-------------+