e1000: fix sparse warning

Sparse complains because the e1000 driver is calling ioread on a pointer
not tagged as __iomem.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/e1000/e1000_osdep.h

@@ -42,7 +42,8 @@
 #define GBE_CONFIG_RAM_BASE \
 	((unsigned int)(CONFIG_RAM_BASE + GBE_CONFIG_OFFSET))
 
-#define GBE_CONFIG_BASE_VIRT    phys_to_virt(GBE_CONFIG_RAM_BASE)
+#define GBE_CONFIG_BASE_VIRT \
+	((void __iomem *)phys_to_virt(GBE_CONFIG_RAM_BASE))
 
 #define GBE_CONFIG_FLASH_WRITE(base, offset, count, data) \
 	(iowrite16_rep(base + offset, data, count))