Replace MBEDTLS_MD_CAN_SHA224 with PSA_WANT_ALG_SHA_224

Signed-off-by: Elena Uziunaite <elena.uziunaite@arm.com>
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index a8807f6..ebeaf5f 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -2527,7 +2527,7 @@
             break;
 #endif
 
-#if defined(MBEDTLS_MD_CAN_SHA224)
+#if defined(PSA_WANT_ALG_SHA_224)
         case MBEDTLS_SSL_HASH_SHA224:
             break;
 #endif