Currently a PCD (e.g. FeaturePCD) cannot be used in a conditional
statement in a DSC/FDF file without a module in the build referencing
the PCD package DEC file.
An example implementation that to support this is to allow a [Packages]
section in the DSC file to list additional package dependencies for PCD
references in the package DSC/FDF files.
this patch is going to add the ability to have the [packages] section
defined in the DSC file
Cc: Liming Gao <liming.gao@intel.com> Cc: Bob Feng <bob.c.feng@intel.com> Signed-off-by: Zhiju.Fan <zhijux.fan@intel.com> Acked-by: Liming Gao <liming.gao@intel.com> Reviewed-by: Bob Feng <bob.c.feng@intel.com>