liquidio: stop using huge static buffer, save 4096k in .data

Only compile-tested - I don't have the hardware.

>From code inspection, octeon_pci_write_core_mem() appears to be safe wrt
unaligned source. In any case, u8 fbuf[] was not guaranteed to be aligned
anyway.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Felix Manlunas <felix.manlunas@cavium.com>
CC: Prasad Kanneganti <prasad.kanneganti@cavium.com>
CC: Derek Chickles <derek.chickles@cavium.com>
CC: David Miller <davem@davemloft.net>
CC: netdev@vger.kernel.org
CC: linux-kernel@vger.kernel.org
Acked-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>