statmount: update STATMOUNT_SUPPORTED macro

According to commit 8f6116b5 ("statmount: add a new supported_mask
field"), STATMOUNT_SUPPORTED macro shall be updated whenever a new flag
is added.

Fixes: 7a54947e ("Merge patch series "fs: allow changing idmappings"")
Signed-off-by: "Dmitry V. Levin" <ldv@strace.io>
Link: https://lore.kernel.org/20250511224953.GA17849@strace.io


Signed-off-by: Christian Brauner <brauner@kernel.org>