net: e1000: Remove unused bus_to_phys() macro

bus_to_phys() is defined but not referenced at all. This patch removes
it completely.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Aaron Williams <awilliams@marvell.com>
Cc: Chandrakala Chavva <cchavva@marvell.com>
diff --git a/drivers/net/e1000.c b/drivers/net/e1000.c
index 7335883..372f6c3 100644
--- a/drivers/net/e1000.c
+++ b/drivers/net/e1000.c
@@ -47,10 +47,8 @@
 
 #ifdef CONFIG_DM_ETH
 #define virt_to_bus(devno, v)	dm_pci_virt_to_mem(devno, (void *) (v))
-#define bus_to_phys(devno, a)	dm_pci_mem_to_phys(devno, a)
 #else
 #define virt_to_bus(devno, v)	pci_virt_to_mem(devno, (void *) (v))
-#define bus_to_phys(devno, a)	pci_mem_to_phys(devno, a)
 #endif
 
 #define E1000_DEFAULT_PCI_PBA	0x00000030