rockchip: set malloc pool size to 0 before relocation in spl state on rk3036 based...

rockchip: set malloc pool size to 0 before relocation in spl state on rk3036 based board

RK3036 only has 4kb sram, the spl code will use
3.4 ~ 3.5 kb, the last 0.5kb are used for SP and
GD, so there is no space for malloc. Also, the spl
will directly return to bootrom after dram initialized,
they never need the space for malloc.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>