ncpfs: return proper error from NCP_IOC_SETROOT ioctl

ncpfs: return proper error from NCP_IOC_SETROOT ioctl

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 ecbd32fd08bb ("BKL: Remove BKL from
ncpfs").  Propagate the errors correctly.

Coverity id: 1226925.

Fixes: ecbd32fd08bb9 ("BKL: Remove BKL from ncpfs")
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Petr Vandrovec <petr@vandrovec.name>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>