EVTCHN Bind method should check that the channel is active
EVTCHN Bind method should check that the channel is active

Any method which performs ABI operations should check whether the channel is
active.

Signed-off-by: Paul Durrant <dba6cd059c0054f8a3c62ba902cd9d7238853ee4@citrix.com>

QubesOS/qubes-vmm-xen-win-pvdrivers-xenbus,omeg/xenbus,MarkKMueller/xenbus,omeg/xenbus,MarkKMueller/xenbus,omeg/xenbus,QubesOS/qubes-vmm-xen-win-pvdrivers-xenbus,MarkKMueller/xenbus,QubesOS/qubes-vmm-xen-win-pvdrivers-xenbus,rneilturner/xenbus,rneilturner/xenbus,rneilturner/xenbus