liquidio: remove obsolete functions and data structures

1. Remove unused functions and data structures.
2. Change the sending of the remaining soft commands to synchronous.

Signed-off-by: Weilin Chang <weilin.chang@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>