Staging: comedi: comedi_fops: Remove unused kmod.h header

Unused after commit f30f2c2d ("staging: comedi:
remove check for CONFIG_KMOD").

Anyway it's included in module.h

Signed-off-by: Cheah Kok Cheong <thrust73@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>