bootchart: call 'bootchart_init' after remount_all is done

In original codes, it call bootchart_init after late_init section.
but the data partition is not mounted yet at that moment. It will
in turn skip bootchart read/write, as it can't read out correct
setting from /data/bootchart-start and write log into correct location.

Fix is to call init function after data partition is ready.

Change-Id: I7c4f268ff94fdcee082399d9e3261f8833b1f8ea