liquidio: optimize reads from Octeon PCI console

Reads from Octeon PCI console are inefficient because before each read
operation, a dynamic mapping to Octeon DRAM is set up.  This patch replaces
the repeated setup of a dynamic mapping with a one-time setup of a static
mapping.

Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: Raghu Vatsavayi <raghu.vatsavayi@cavium.com>
Signed-off-by: Derek Chickles <derek.chickles@cavium.com>
Signed-off-by: Satanand Burla <satananda.burla@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>