Reverts commit ead38dbc9d
It was introduced as a temporal workaround to avoid the endless restart
loop when battery is low, but really it is useless. The bootloader should
ensure that there is enough power to launch Rockbox even in the worst
scenario.
Change-Id: Iabebed40c9241af915c16c3c6c4d3c6deef7680e
e2f943f229