netxen: firmware init fix

o Fix order or rom register writes.
o Reduce udelays when writing rom registers.

This cuts the firmware init time by 40%.

o Do not reset core/memory clocks when reinitializing driver.
  Firmware willl handle this when initialized.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>