ncpfs: return proper error from NCP_IOC_SETROOT ioctl

commit a682e9c28cac152e6e54c39efcf046e0c8cfcf63 upstream.

If some error happens in NCP_IOC_SETROOT ioctl, the appropriate error
return value is then (in most cases) just overwritten before we return.
This can result in reporting success to userspace although error happened.

This bug was introduced by commit 2e54eb96 ("BKL: Remove BKL from
ncpfs").  Propagate the errors correctly.

Coverity id: 1226925.

Fixes: 2e54eb96 ("BKL: Remove BKL from ncpfs")
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>