net/enic: fix crash when releasing queues
net/enic: fix crash when releasing queues

If device configuration failed due to a lack of resources, such as
if more queues are requested than are available, the queue release
functions are called with NULL pointers which were being dereferenced.

Skip releasing queues if they are NULL pointers.

Fixes: fefed3d1e62c ("enic: new driver")

Signed-off-by: John Daley <097981eb5abe5dbeac3142a4f5a88742d916de86@cisco.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk