Revert "SPM: Add STATUS_NEED_SCHEDULE to manage scheduler"

This reverts commit 9e38935fabf7eae9d54a550bd578163ec9ca1f99.

Reason for revert: Nightly test issue.

Change-Id: I68af7380bd5aa3f9be8363b52b261b1cf310cd59
diff --git a/secure_fw/spm/ffm/psa_api.c b/secure_fw/spm/ffm/psa_api.c
index 7a46c04..1f1c715 100644
--- a/secure_fw/spm/ffm/psa_api.c
+++ b/secure_fw/spm/ffm/psa_api.c
@@ -530,11 +530,11 @@
 }
 
 #if CONFIG_TFM_DOORBELL_API == 1
-psa_status_t tfm_spm_partition_psa_notify(int32_t partition_id)
+void tfm_spm_partition_psa_notify(int32_t partition_id)
 {
     struct partition_t *p_pt = tfm_spm_get_partition_by_id(partition_id);
 
-    return backend_assert_signal(p_pt, PSA_DOORBELL);
+    backend_assert_signal(p_pt, PSA_DOORBELL);
 }
 
 void tfm_spm_partition_psa_clear(void)