[nrf noup] include md.h in psa_util.h

Make definitions from md.h available in psa_util.h.

This change is re-applied from commit
2cc273b that was reverted to undo some
of its changes.

This is needed otherwise we get errors regarding missing definitions,
e.g. of mbedtls_md_type_t in mbedtls_md_type_from_psa_alg().

Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>

Author: tomi-font

include/mbedtls/psa_util.h

@@ -13,6 +13,7 @@
 #include "mbedtls/private_access.h"
 
 #include "mbedtls/build_info.h"
+#include "mbedtls/md.h"
 
 #include "psa/crypto.h"