board: ae350: Add missing env variables for booti

The 'booti' command is unable to boot Image.gz due to the absence
of required environment variables 'kernel_comp_addr_r' and
'kernel_comp_size'.

This commit adds these variables and reorganizes the memory layout
to prevent any overlap between binaries and files.

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>