Use helper macro in ext/exif (#14352)

Author: nielsdos

ext/exif/exif.c

@@ -73,7 +73,7 @@ PHP_MINFO_FUNCTION(exif)
 	php_info_print_table_row(2, "Supported EXIF Version", "0220");
 	php_info_print_table_row(2, "Supported filetypes", "JPEG, TIFF");
 
-	if (zend_hash_str_exists(&module_registry, "mbstring", sizeof("mbstring")-1)) {
+	if (USE_MBSTRING) {
 		php_info_print_table_row(2, "Multibyte decoding support using mbstring", "enabled");
 	} else {
 		php_info_print_table_row(2, "Multibyte decoding support using mbstring", "disabled");