liquidio: standardization: use min_t instead of custom macro

Signed-off-by: Rick Farrington <ricardo.farrington@cavium.com>
Signed-off-by: Derek Chickles <derek.chickles@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>