powerpc/t4240: enable NAND boot support

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
diff --git a/boards.cfg b/boards.cfg
index c602a16..5d81e9f 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -966,6 +966,7 @@
 Active  powerpc     mpc85xx        -           freescale       t4qds               T4160QDS_SPIFLASH                    T4240QDS:PPC_T4160,RAMBOOT_PBL,SPIFLASH,SYS_TEXT_BASE=0xFFF80000                                                                  -
 Active  powerpc     mpc85xx        -           freescale       t4qds               T4240EMU                             T4240EMU:PPC_T4240                                                                                                                York Sun <yorksun@freescale.com>
 Active  powerpc     mpc85xx        -           freescale       t4qds               T4240QDS                             T4240QDS:PPC_T4240                                                                                                                -
+Active  powerpc     mpc85xx        -           freescale       t4qds               T4240QDS_NAND	                T4240QDS:PPC_T4240,RAMBOOT_PBL,NAND,SYS_TEXT_BASE=0xFFF80000                                                                      -
 Active  powerpc     mpc85xx        -           freescale       t4qds               T4240QDS_SDCARD                      T4240QDS:PPC_T4240,RAMBOOT_PBL,SDCARD,SYS_TEXT_BASE=0xFFF80000                                                                    -
 Active  powerpc     mpc85xx        -           freescale       t4qds               T4240QDS_SPIFLASH                    T4240QDS:PPC_T4240,RAMBOOT_PBL,SPIFLASH,SYS_TEXT_BASE=0xFFF80000                                                                  -
 Active  powerpc     mpc85xx        -           freescale       t4qds               T4240QDS_SRIO_PCIE_BOOT              T4240QDS:PPC_T4240,SRIO_PCIE_BOOT_SLAVE,SYS_TEXT_BASE=0xFFF80000                                                                  -