schedule: use k_thread_cpu_pin() for CPU affinity

Replace the k_thread_cpu_mask_clear() + k_thread_cpu_mask_enable()
sequence with a single k_thread_cpu_pin() call.

The clear-then-enable pattern momentarily leaves the thread with a
zero CPU mask, which is invalid under CONFIG_SCHED_CPU_MASK_PIN_ONLY
and triggers an assertion after Zephyr commit 7798570a031d ("kernel:
sched: enforce non-zero CPU mask invariant in PIN_ONLY mode").

k_thread_cpu_pin() atomically sets exactly one bit in the mask,
avoiding the transient zero-mask state.

Signed-off-by: Jyri Sarha <jyri.sarha@linux.intel.com>

Author: Jyri Sarha

src/schedule/zephyr_dma_domain.c

@@ -462,8 +462,7 @@ static int zephyr_dma_domain_register(struct ll_schedule_domain *domain,
 				 K_FOREVER);
 
 #ifdef CONFIG_SCHED_CPU_MASK
-	k_thread_cpu_mask_clear(thread);
-	k_thread_cpu_mask_enable(thread, core);
+	k_thread_cpu_pin(thread, core);
 #endif
 	k_thread_name_set(thread, thread_name);
 

src/schedule/zephyr_domain.c

@@ -218,8 +218,7 @@ static int zephyr_domain_register(struct ll_schedule_domain *domain,
 				 NULL, CONFIG_LL_THREAD_PRIORITY, 0, K_FOREVER);
 
 #ifdef CONFIG_SCHED_CPU_MASK
-	k_thread_cpu_mask_clear(thread);
-	k_thread_cpu_mask_enable(thread, core);
+	k_thread_cpu_pin(thread, core);
 #endif
 	k_thread_name_set(thread, thread_name);
 
@@ -345,8 +344,7 @@ static int zephyr_domain_thread_init(struct ll_schedule_domain *domain,
 				 K_USER, K_FOREVER);
 
 #ifdef CONFIG_SCHED_CPU_MASK
-	k_thread_cpu_mask_clear(thread);
-	k_thread_cpu_mask_enable(thread, core);
+	k_thread_cpu_pin(thread, core);
 #endif
 	k_thread_name_set(thread, thread_name);
 

zephyr/edf_schedule.c

@@ -117,8 +117,7 @@ __cold int scheduler_init_edf(void)
 
 	k_thread_heap_assign(thread, sof_sys_heap_get());
 #ifdef CONFIG_SCHED_CPU_MASK
-	k_thread_cpu_mask_clear(thread);
-	k_thread_cpu_mask_enable(thread, PLATFORM_PRIMARY_CORE_ID);
+	k_thread_cpu_pin(thread, PLATFORM_PRIMARY_CORE_ID);
 #endif
 	k_thread_name_set(thread, "edf_workq");