x86: lib: fsp: Use EFI_GUID and efi_guid_t

Use existing EFI_GUID and efi_guid_t instead of struct efi_guid.
This is pre-work before making a common HOB library.
- Change 'struct efi_guid' to efi_guit_t
- Remove 'struct efi_guid'
- Define GUIDs with EFI_GUID() macro
- Use guidcmp() instead of compare_guid()
- Remove compare_guid()

Signed-off-by: Aiden Park <aiden.park@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Tested on MinnowMax
Tested-by: Bin Meng <bmeng.cn@gmail.com>