RDMA/ocrdma: Read ASIC_ID register to select asic_gen

ocrdma driver selects execution path based on sli_family and asic
generation number.  This introduces code to read the asic gen number
from pci register instead of obtaining it from the Emulex NIC driver.

Signed-off-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Selvin Xavier <selvin.xavier@emulex.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>