[media] staging: lirc_serial: Fix bogus error codes

Device not found?  ENODEV, not EINVAL.
Write to read-only device?  EPERM, not EBADF.
Invalid argument?  EINVAL, not ENOSYS.
Unsupported ioctl?  ENOIOCTLCMD, not ENOSYS.
Another function returned an error code?  Use that, don't replace it.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>