image: Use gd->ram_base/_size in env_get_bootm_size()

Use only gd->ram_base/_size in env_get_bootm_size() instead of bi_dram[]
in some cases and bi_memstart in others.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
1 file changed