acpi: Add an acpi command to list/dump generated ACPI items

Add a command that shows the individual blocks of data generated by each
device, effectively splitting the full table into its component parts.
This can be helpful for debugging.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>