staging: comedi: pcmmio: remove unneeded checks on detach
staging: comedi: pcmmio: remove unneeded checks on detach

As pointed out by Dan carpenter for the similar pcmuio driver, there is
no need to check the pointer passed to `kfree()`, so remove that check
from `pcmmio_detach()`.

Also, check the `devpriv` (`dev->private`) pointer once, outside the
`for` loop.

Signed-off-by: Ian Abbott <9e6ba6483b6a3e14d61f7c987e72ecb5b46122d6@mev.co.uk>
Cc: Dan Carpenter <ff341aa343d564f9e53e9dcb6996be8c04859a66@oracle.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs