riscv: dts: move out AE350 L2 node from cpus node

riscv: dts: move out AE350 L2 node from cpus node

When L2 node exists inside cpus node, uclass_get_device
can not parse L2 node successfully. So move it outside
from cpus node.

Also add tag-ram-ctl and data-ram-ctl attributes for
v5l2 cache controller driver. This can adjust timing
by requirement from dtb to improve performance.

Signed-off-by: Rick Chen <rick@andestech.com>
Cc: KC Lin <kclin@andestech.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>