staging: gasket: interrupt: remove PCI-MSIX-specific status check

Devices not using MSIX don't use the msix_initialized field, so don't
require it to be set in the interrupt system status check. The general
check for interrupts configured that follows can cover both MSIX and
device-managed interrupts.

Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>