SPM: Treat more irq load info as const

Signed-off-by: Chris Brand <chris.brand@cypress.com>
Change-Id: I948030ff0b349e27ca5d61401b66c805fe2f4d9f
diff --git a/secure_fw/spm/ffm/interrupt.c b/secure_fw/spm/ffm/interrupt.c
index 463676a..b52add8 100644
--- a/secure_fw/spm/ffm/interrupt.c
+++ b/secure_fw/spm/ffm/interrupt.c
@@ -112,12 +112,12 @@
 }
 #endif
 
-struct irq_load_info_t *get_irq_info_for_signal(
+const struct irq_load_info_t *get_irq_info_for_signal(
                                     const struct partition_load_info_t *p_ldinf,
                                     psa_signal_t signal)
 {
     size_t i;
-    struct irq_load_info_t *irq_info;
+    const struct irq_load_info_t *irq_info;
 
     if (!IS_ONLY_ONE_BIT_IN_UINT32(signal)) {
         return NULL;
@@ -133,7 +133,7 @@
     return NULL;
 }
 
-void spm_handle_interrupt(void *p_pt, struct irq_load_info_t *p_ildi)
+void spm_handle_interrupt(void *p_pt, const struct irq_load_info_t *p_ildi)
 {
     psa_flih_result_t flih_result;
     struct partition_t *p_part;