idmapped-mounts: account for EOVERFLOW

idmapped-mounts: account for EOVERFLOW

We introduced a new type vfs{g,u}id_t into the vfs in b27c82e12965
("attr: port attribute changes to new types"). This type makes sure that
{g,u}ids mapped into an idmapped mount are distinct from regular
k{g,u}id_t. This expands the possible errnos that users may see so we
need to handle both EINVAL and EOVERFLOW.

Cc: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>