ADAC: Add stub close session functionality

Add stub implementation of the psa_adac_close_session command for the
platforms to implement custom terminate session functionality.

Signed-off-by: Maulik Patel <maulik.patel@arm.com>
Change-Id: Id584ee3b6c5f7d177fe38584f266b1f057b690dc
diff --git a/template_hal_files/target_name.c b/template_hal_files/target_name.c
index eb70cab..8704bd3 100644
--- a/template_hal_files/target_name.c
+++ b/template_hal_files/target_name.c
@@ -28,7 +28,7 @@
     return ADAC_UNSUPPORTED;
 }
 
-void psa_adac_platform_lock(void)
+void psa_adac_close_session(void)
 {
     /* TODO: Code me */
 }
@@ -38,6 +38,11 @@
     /* TODO: Code me */
 }
 
+void psa_adac_platform_lock(void)
+{
+    /* TODO: Code me */
+}
+
 int psa_adac_platform_check_token(uint8_t *token, size_t token_size)
 {
     /* TODO: Code me */