board/t2080rdb: some update for t2080rdb

- update readme.
- add CONFIG_SYS_CORTINA_FW_IN_* for loading Cortina PHY CS4315
  ucode from NOR/NAND/SPI/SD/REMOTE.
- update cpld vbank with SW3[5:7]=000 as default vbank0 instead of
  previous SW3[5:7]=111 as default vbank.
- fix CONFIG_SYS_I2C_EEPROM_ADDR_LEN to 2.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/board/freescale/t208xrdb/cpld.h b/board/freescale/t208xrdb/cpld.h
index 4cee4e5..3f15338 100644
--- a/board/freescale/t208xrdb/cpld.h
+++ b/board/freescale/t208xrdb/cpld.h
@@ -35,8 +35,8 @@
 #define CPLD_LBMAP_MASK		0x3F
 #define CPLD_BANK_SEL_MASK	0x07
 #define CPLD_BANK_OVERRIDE	0x40
-#define CPLD_LBMAP_ALTBANK	0x43 /* BANK OR | BANK 4 */
-#define CPLD_LBMAP_DFLTBANK	0x47 /* BANK OR | BANK 0 */
+#define CPLD_LBMAP_ALTBANK	0x44 /* BANK OR | BANK 4 */
+#define CPLD_LBMAP_DFLTBANK	0x40 /* BANK OR | BANK 0 */
 #define CPLD_LBMAP_RESET	0xFF
 #define CPLD_LBMAP_SHIFT	0x03
 #define CPLD_BOOT_SEL		0x80