OMAP: common: consolidate fake USB ethernet MAC address creation

TI platforms such as OMAP5uevm, PandaBoard, use equivalent
logic to generate fake USB MAC address from device unique DIE ID.

Consolidate this to a generic location such that other TI platforms such
as BeagleBoard-XM can also use the same.

NOTE: at this point in time, I dont yet see a need for a generic dummy
ethernet MAC address creation function, but if there is a need in the
future, this can be further abstracted out.

Signed-off-by: Nishanth Menon <nm@ti.com>
diff --git a/board/ti/panda/panda.c b/board/ti/panda/panda.c
index 0dfb4ad..16368cb 100644
--- a/board/ti/panda/panda.c
+++ b/board/ti/panda/panda.c
@@ -193,7 +193,7 @@
 {
 	int phy_type;
 	u32 auxclk, altclksrc;
-	uint8_t device_mac[6];
+	u32 id[4];
 
 	/* EHCI is not supported on ES1.0 */
 	if (omap_revision() == OMAP4430_ES1_0)
@@ -247,20 +247,11 @@
 
 	writel(altclksrc, &scrm->altclksrc);
 
-	if (!getenv("usbethaddr")) {
-		/*
-		 * create a fake MAC address from the processor ID code.
-		 * first byte is 0x02 to signify locally administered.
-		 */
-		device_mac[0] = 0x02;
-		device_mac[1] = readl(STD_FUSE_DIE_ID_3) & 0xff;
-		device_mac[2] = readl(STD_FUSE_DIE_ID_2) & 0xff;
-		device_mac[3] = readl(STD_FUSE_DIE_ID_1) & 0xff;
-		device_mac[4] = readl(STD_FUSE_DIE_ID_0) & 0xff;
-		device_mac[5] = (readl(STD_FUSE_DIE_ID_0) >> 8) & 0xff;
-
-		eth_setenv_enetaddr("usbethaddr", device_mac);
-	}
+	id[0] = readl(STD_FUSE_DIE_ID_0);
+	id[1] = readl(STD_FUSE_DIE_ID_1);
+	id[2] = readl(STD_FUSE_DIE_ID_2);
+	id[3] = readl(STD_FUSE_DIE_ID_3);
+	usb_fake_mac_from_die_id(id);
 
 	return 0;
 }