Several Broadcom targets were using the nand_do_upgrade_success shell function which has been removed by commite25e6d8e54("base-files: fix and clean up nand sysupgrade code"). Refactor the new nand_do_upgrade to bring back nand_do_upgrade_success with the behavior expected by those users. Fixes:e25e6d8e54("base-files: fix and clean up nand sysupgrade code") Reported-by: Chen Minqiang <ptpt52@gmail.com> Signed-off-by: Daniel Golle <daniel@makrotopia.org>