md: fix guards for mbedtls_md_error_from_psa()

This should be CRYPTO_CLIENT and not CRYPTO_C as this function
can be used even when CRYPTO_C is not defined.

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/md.c b/library/md.c
index 12a3ea2..c95846a 100644
--- a/library/md.c
+++ b/library/md.c
@@ -41,7 +41,7 @@
 #include "mbedtls/sha512.h"
 #include "mbedtls/sha3.h"
 
-#if defined(MBEDTLS_PSA_CRYPTO_C)
+#if defined(MBEDTLS_PSA_CRYPTO_CLIENT)
 #include <psa/crypto.h>
 #include "md_psa.h"
 #include "psa_util_internal.h"
@@ -761,13 +761,13 @@
     return md_info->type;
 }
 
-#if defined(MBEDTLS_PSA_CRYPTO_C)
+#if defined(MBEDTLS_PSA_CRYPTO_CLIENT)
 int mbedtls_md_error_from_psa(psa_status_t status)
 {
     return PSA_TO_MBEDTLS_ERR_LIST(status, psa_to_md_errors,
                                    psa_generic_status_to_mbedtls);
 }
-#endif /* MBEDTLS_PSA_CRYPTO_C */
+#endif /* MBEDTLS_PSA_CRYPTO_CLIENT */
 
 
 /************************************************************************