Replace MBEDTLS_MD_CAN_SHA224 with PSA_WANT_ALG_SHA_224

Signed-off-by: Elena Uziunaite <elena.uziunaite@arm.com>
diff --git a/library/x509.c b/library/x509.c
index f97fb44..4aa612c 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -137,7 +137,7 @@
         case MBEDTLS_MD_SHA1:
             return "SHA1";
 #endif
-#if defined(MBEDTLS_MD_CAN_SHA224)
+#if defined(PSA_WANT_ALG_SHA_224)
         case MBEDTLS_MD_SHA224:
             return "SHA224";
 #endif