sd-boot: select newest kernel entry matching with the default glob pattern

This fixes a bug introduced by 0c674ce5f2.

Fixes #22004.

src/boot/efi/boot.c

@@ -1638,9 +1638,9 @@ static INTN config_entry_find(Config *config, const CHAR16 *needle) {
         if (!needle)
                 return -1;
 
-        for (UINTN i = 0; i < config->entry_count; i++)
+        for (INTN i = config->entry_count - 1; i >= 0; i--)
                 if (MetaiMatch(config->entries[i]->id, (CHAR16*) needle))
-                        return (INTN) i;
+                        return i;
 
         return -1;
 }