85xx/86xx: Rename ext_refrec to timing_cfg_3 to match docs

All the 85xx and 86xx UM describe the register as timing_cfg_3
not as ext_refrec.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/board/freescale/mpc8610hpcd/mpc8610hpcd.c b/board/freescale/mpc8610hpcd/mpc8610hpcd.c
index d9a740e..3a855b5 100644
--- a/board/freescale/mpc8610hpcd/mpc8610hpcd.c
+++ b/board/freescale/mpc8610hpcd/mpc8610hpcd.c
@@ -192,7 +192,7 @@
 	ddr->cs0_bnds = 0x0000001f;
 	ddr->cs0_config = 0x80010202;
 
-	ddr->ext_refrec = 0x00000000;
+	ddr->timing_cfg_3 = 0x00000000;
 	ddr->timing_cfg_0 = 0x00260802;
 	ddr->timing_cfg_1 = 0x3935d322;
 	ddr->timing_cfg_2 = 0x14904cc8;