staging: gpib: fix address space mixup

Throughout the gpib drivers, a 'void *' struct member is used in place
of either port numbers or __iomem pointers, which leads to lots of extra
type casts, sparse warnings and less portable code.

Split the struct member in two separate ones with the correct types,
so each driver can pick which one to use.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/all/f10e976e-7a04-4454-b38d-39cd18f142da@roeck-us.net/
Link: https://lore.kernel.org/r/20241213064959.1045243-3-arnd@kernel.org


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