x86: apl: Use devicetree for FSP-M configuration

x86: apl: Use devicetree for FSP-M configuration

A the moment the FSP-M configuration is a mix of hard coded values and
devicetree properties.

This patch makes FSP-M full configurable from devicetree by adding
binding properties for all FSP-M parameters.

Co-developed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Signed-off-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Signed-off-by: Bernhard Messerklinger <bernhard.messerklinger@br-automation.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org> (Tested on coral)
[sjg: Fix a build error for coral]
Signed-off-by: Simon Glass <sjg@chromium.org>
[bmeng: Add __maybe_unused to fsp_update_config_from_dtb()]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>