[][OpenWrt Dev][nmbm: change the api of reading page from lower device]

Change the return value of the lower read page API to make
sure bitflip information can be passed to upper layer.

The return value of reading page now is:
0 for success, positive for corrected bitflip(s),
-EBADMSG for uncorrectable bitflips, other positive for error


Change-Id: I9657e6b07abe6c130ccd5e1670ed247e1a0c83db
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/4649342
1 file changed