ASoC: Intel: soc-acpi-intel-mtl-match: add missing empty item

There is no links_num in struct snd_soc_acpi_mach {}, and we test
!link->num_adr as a condition to end the loop in hda_sdw_machine_select().
So an empty item in struct snd_soc_acpi_link_adr array is required.

Fixes: f77ae7fcdc4763 ("ASoC: Intel: soc-acpi-intel-mtl-match: add cs42l43 only support")
Signed-off-by: Bard Liao <[e-mail]>
Reviewed-by: Ranjani Sridharan <[e-mail]>
Reviewed-by: Péter Ujfalusi <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/intel/common/soc-acpi-intel-mtl-match.c

···
 		.num_adr = ARRAY_SIZE(cs42l43_0_adr),
 		.adr_d = cs42l43_0_adr,
 	},
+	{}
 };
 
 static const struct snd_soc_acpi_link_adr mtl_cs42l43_cs35l56[] = {