staging: gpib: Remove unused enums from common include file

The error code and timeout code enums are not used by any
of the gpib kernel code.  This patch removes them.

Signed-off-by: Dave Penkler <dpenkler@gmail.com>
Link: https://lore.kernel.org/r/20250418093111.8820-2-dpenkler@gmail.com


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