staging: gpib: Remove unneeded enums and functions

Remove enums and functions that do not need to be shared
with user space.

Remove enums and functions that are not needed in the kernel drivers.

Signed-off-by: Dave Penkler <dpenkler@gmail.com>
Link: https://lore.kernel.org/r/20250603184320.30594-2-dpenkler@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>