staging: gpib: Use C99 syntax and make static

staging: gpib: Use C99 syntax and make static

Some drivers were still using the old syntax for initializing
structs:
field : value;

This caused sparse to emit the following warning, for example:
common/gpib_os.c:2026:1: warning: obsolete struct initializer, use C99 syntax

Use C99 syntax:
.field = value;

Some local structs and arrays were not declared static causing
sparse to emit the following warning, for example:
warning: symbol 'ib_fops' was not declared. Should it be static?

Declare the local structs and arrays as static.

Signed-off-by: Dave Penkler <dpenkler@gmail.com>
Link: https://lore.kernel.org/r/20250114165403.16410-5-dpenkler@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>