USB: xHCI: re-initialize cmd_completion

When a signal interrupts a Configure Endpoint command, the cmd_completion used
in xhci_configure_endpoint() is not re-initialized and the
wait_for_completion_interruptible_timeout() will return failure. Initialize
cmd_completion in xhci_configure_endpoint().

Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>