Merge branch 'xen-netback-fixes'

Paul Durrant says:

====================
xen-netback: update memory leak fix to avoid BUG

Commit 9a6cdf52b85e "xen-netback: fix memory leaks on XenBus disconnect"
added missing code to fix a memory leak by calling vfree() in the
appropriate place.
Unfortunately subsequent commit f16f1df65f1c "xen-netback: protect
resource cleaning on XenBus disconnect" then wrapped this call to vfree()
in a spin lock, leading to a BUG due to incorrect context.

Patch #1 makes the existing code more readable
Patch #2 fixes the problem
====================

Signed-off-by: David S. Miller <davem@davemloft.net>