[ofw] [PATCH v2] don't include initguid in interface headers

[Hefty, Sean]

> Updated based on Sean's comments, including adding the #ifdef DEFINE_GUID
> for all other interface files.
> 
> Signed-off-by: Fab Tillier <ftillier at microsoft.com>

Acked-by: Sean Hefty <sean.hefty at intel.com>