staging: comedi: comedi.h: Do not use BIT macro

The "comedi.h" file is part of the user API for COMEDI devices, and is
intended to be migrated to "include/uapi/linux".  The `BIT` macro from
"include/linux/bitops.h" should not be used there.

Replace the use of the `BIT` macro with hexadecimal constants of the
same value.  The `BIT` macro replaced expressions of the form `(1 << N)`
in this file originally, but reverting back to that form would encourage
patches changing them back to use the `BIT` macro.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>