x86: fsp: Rename shared_data to fsp_config_data

FSP has several config data like UPD, HDA verb table which can be
overridden or provided by bootloader. Currently in U-Boot only UPD
is handled via struct shared_data. To accommodate any platform, we
rename shared_data to fsp_config_data and move the definition from
common place fsp_support.h to platform-specific place fsp_configs.h.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>