feat(bl): adding psa crypto - crypto_mod_finish()

Adding call to crypto_mod_finish() at the end of crypto usage in the
bl mains. This is currently used for psa crytpo to destroy the
psa_key_ids in the psa key store, but could be expanded if required
later.

Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
Change-Id: I3dba9fe87b6bb64b629dda9d6c4653b116e7ee62
diff --git a/bl1/bl1_main.c b/bl1/bl1_main.c
index db14ec6..fba9102 100644
--- a/bl1/bl1_main.c
+++ b/bl1/bl1_main.c
@@ -134,6 +134,8 @@
 	/* Teardown the measured boot driver */
 	bl1_plat_mboot_finish();
 
+	crypto_mod_finish();
+
 	bl1_prepare_next_image(image_id);
 
 #if ENABLE_RUNTIME_INSTRUMENTATION