netxen: added miniDIMM support in driver.

Driver queries DIMM information from firmware and accordingly
sets "presence" field of the structure.
"presence" field when set to 0xff denotes invalid flag. And when
set to 0x0 denotes DIMM memory is not present.

Signed-off-by: Sucheta Chakraborty <sucheta.chakraborty@qlogic.com>
Signed-off-by: Rajesh Borundia <rajesh.borundia@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>