common: Chown mount even if already idmapped to account for remounts

common: Chown mount even if already idmapped to account for remounts

This is a logical consequence of introducing the chown check in _idmapped_mount,
since now a read-only mount can be made idmapped successfully. But if the mount
is then remounted rw the chown never happens, as _idmapped_mount sees that it's
already idmapped and bows out early.

This patch fixes that by simply moving the chown ahead of the idmapped check,
so it will be performed in any case, even on already idmapped mounts.

Signed-off-by: Gabriel Niebler <gniebler@suse.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>