BOOT-UP: even if the cpu has been configured to boot up from mmc1(RAW), bootloader will now trying to load "kernel" and "rootfs" from mmc0 (with FAT filesystem) first. If failed, then we will try mmc1.

git-svn-id: https://192.168.1.10:1230/svn/%E6%8A%80%E6%9C%AF%E7%BB%84SVN@22 cc96f0a0-d58f-8a49-aa02-fe85e0dd7cbe
BOOT-UP: support dual-boot from tf-card and eMMC.
BOOT-TIME:1.cancel delay in raw-mode, in fat-mode, the delay is set to 1s
2.cancel kernel verification, save 1s
3.disable debug info
4.force eMMC bus width at 4-bit
PARTITION-TABLE: preserve the partition table in eMMC

git-svn-id: https://192.168.1.10:1230/svn/%E6%8A%80%E6%9C%AF%E7%BB%84SVN@23 cc96f0a0-d58f-8a49-aa02-fe85e0dd7cbe
BOOTUP-TIME: eMMCsupport boots up in 8-bit mode.(currently toshiba only)

git-svn-id: https://192.168.1.10:1230/svn/%E6%8A%80%E6%9C%AF%E7%BB%84SVN@24 cc96f0a0-d58f-8a49-aa02-fe85e0dd7cbe