staging: gpib: make port I/O code conditional

staging: gpib: make port I/O code conditional

A few of the helper modules contain functions for both IORESOURCE_MEM
and IORESOURCE_IO type access, with the latter not being supported
on all architectures but also not used by all the drivers.

Add #ifdef checks around these to allow building the library code
and use it on MMIO-only configurations.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20241016111521.1143191-5-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>