Add missing include

Fix build failures with config full

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 9a4cfdb..399e7f3 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -82,6 +82,7 @@
 #include "mbedtls/sha1.h"
 #include "mbedtls/sha256.h"
 #include "mbedtls/sha512.h"
+#include "md_psa.h"
 
 #define ARRAY_LENGTH(array) (sizeof(array) / sizeof(*(array)))