liquidio: fix Coverity scan errors

Fix Coverity scan errors by not dereferencing lio->glists_dma_base pointer
if it's NULL.

See http://marc.info/?l=linux-netdev&m=149002294305614&w=2



Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: VSR Burru <veerasenareddy.burru@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>