ext2: move ext2_xattr_handlers and ext2_xattr_handler_map to .rodata

This makes it harder for accidental or malicious changes to
ext2_xattr_handlers or ext2_xattr_handler_map at runtime.

Cc: Jan Kara <jack@suse.com>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230930050033.41174-10-wedsonaf@gmail.com


Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>