[edk2] [Basetool][Ecc][patch5]Fix a bug to not break when parsing a macro and not find its value

[Chen, Hesheng]

Hello Yang and all,
Could you help review this patch? Thank you

[Description]
Fix a bug to not break when parsing a macro and not find its value

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hess Chen <***@intel.com<mailto:***@intel.com> >


Best Regards,
Chen, Hess
Intel China Software Center
Tel: [phone]
Email: ***@intel.com<mailto:***@intel.com>