[legacy] Allocate legacy driver .bss-like segments at probe time

Some legacy drivers use large static allocations for transmit and
receive buffers.  To avoid bloating the .bss segment, we currently
implement these as a single common symbol named "_shared_bss" (which
is permissible since only one legacy driver may be active at any one
time).

Switch to dynamic allocation of these .bss-like segments, to avoid the
requirement for using common symbols.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/3c595.c

@@ -541,7 +541,7 @@ PCI_ROM(0x10b7, 0x9805, "3c9805-1",        "3Com9805", 0),		/* Dual Port Server
 PCI_DRIVER ( t595_driver, t595_nics, PCI_NO_CLASS );
 
 DRIVER ( "3C595", nic_driver, pci_driver, t595_driver,
-	 t595_probe, t595_disable );
+	 t595_probe, t595_disable, no_fake_bss );
 
 /*
  * Local variables: