[TG3]: Add indirect register method for 5703 behind ICH

[TG3]: Add indirect register method for 5703 behind ICH

This patch adds the new workaround for 5703 A1/A2 if it is behind
certain ICH bridges. The workaround disables memory and uses config.
cycles only to access all registers. The 5702/03 chips can mistakenly
decode the special cycles from the ICH chipsets as memory write cycles,
causing corruption of register and memory space. Only certain ICH
bridges will drive special cycles with non-zero data during the address
phase which can fall within the 5703's address range. This is not an ICH
bug as the PCI spec allows non-zero address during special cycles.
However, only these ICH bridges are known to drive non-zero addresses
during special cycles.

The indirect_lock is also changed to spin_lock_irqsave from spin_lock_bh
because it is used in irq handler when using the indirect method to
disable interrupts.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>