net.h: Include linux/if_ether.h to avoid duplication

There are plenty of existing drivers that have macros like ETH_ALEN
defined in their own source files. Now that we imported the kernel's
if_ether.h to U-Boot we can reduce some duplication.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/include/net.h b/include/net.h
index 2b2deb5..156bdc1 100644
--- a/include/net.h
+++ b/include/net.h
@@ -14,6 +14,7 @@
 
 #include <asm/cache.h>
 #include <asm/byteorder.h>	/* for nton* / ntoh* stuff */
+#include <linux/if_ether.h>
 
 #define DEBUG_LL_STATE 0	/* Link local state machine changes */
 #define DEBUG_DEV_PKT 0		/* Packets or info directed to the device */