1.don't update vpc when record vpc equals 0 in gc progress
2.increase the number of read retry
3.avoid danger of abnormal power lost
4.change flash_read_page_raw return to error_ecc_bits
5.add nand buildin ecc support
6.skip ECC error page instead of marking as bad block
7.adjust the way of building tables to increase ftl init
Change-Id: I9ba24980c06d61a5a1d66019378075e0171a5887
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>