lmb: introduce a function to add memory to the lmb memory map

lmb: introduce a function to add memory to the lmb memory map

Introduce a function lmb_add_memory() to add available memory to the
LMB memory map. Call this function during board init once the LMB data
structures have been initialised.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>