riscv: ae350: enable Coherence Manager for ae350

If Coherence Manager were not set in the beginning,
u-boot-spl would sometimes fail to boot to u-boot proper.

Enable CM and I/D cache at the same time in harts_early_init

Signed-off-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Rick Chen <rick@andestech.com>