staging: gpib: fix unset padding field copy back to userspace

The introduction of a padding field in the gpib_board_info_ioctl is
showing up as initialized data on the stack frame being copyied back
to userspace in function board_info_ioctl. The simplest fix is to
initialize the entire struct to zero to ensure all unassigned padding
fields are zero'd before being copied back to userspace.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Fixes: 9dde4559 ("staging: gpib: Add GPIB common core driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20250623220958.280424-1-colin.i.king@gmail.com


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