vboxsf: Avoid an spurious warning if load_nls_xxx() fails

vboxsf: Avoid an spurious warning if load_nls_xxx() fails

If an load_nls_xxx() function fails a few lines above, the 'sbi->bdi_id' is
still 0.
So, in the error handling path, we will call ida_simple_remove(..., 0)
which is not allocated yet.

In order to prevent a spurious "ida_free called for id=0 which is not
allocated." message, tweak the error handling path and add a new label.

Fixes: 0fd169576648 ("fs: Add VirtualBox guest shared folder (vboxsf) support")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/d09eaaa4e2e08206c58a1a27ca9b3e81dc168773.1698835730.git.christophe.jaillet@wanadoo.fr
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>