CbPlatformSupportLib might use FindCbTag() API to parse
platform specific information. So expose this API.
And add EFIAPI to all functions in CbParseLib.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Guo Dong <guo.dong@intel.com>
Reviewed-by: Maurice Ma <maurice.ma@intel.com>