Revert "rockchip: Reconfigure the malloc based to point to system memory"

This patch was merged shortly before the v2015.10 as a minimal fix for
booting on rockchip. Now that the patch series from Hans to do the
relocation in generic code has been merged it can be dropped.

This reverts commit b1f492ca.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Acked-by: Simon Glass <sjg@chromium.org>