SPM: Rename 'irq_defs' into 'interrupt_defs'

'irq' looks a bit constraint which is not aligned with
the header file name in the same folder.

Change-Id: Ib3e003bfdfa8d30d01d85cb8ba078e86c27f3703
Signed-off-by: Ken Liu <Ken.Liu@arm.com>
diff --git a/secure_fw/spm/ffm/psa_api.c b/secure_fw/spm/ffm/psa_api.c
index ea6a098..4036e97 100644
--- a/secure_fw/spm/ffm/psa_api.c
+++ b/secure_fw/spm/ffm/psa_api.c
@@ -14,7 +14,7 @@
 #include "tfm_core_utils.h"
 #include "load/partition_defs.h"
 #include "load/service_defs.h"
-#include "load/irq_defs.h"
+#include "load/interrupt_defs.h"
 #include "psa_api.h"
 #include "utilities.h"
 #include "tfm_wait.h"