platform: add a mechanism for AFU's to set platform macros (#3130)

Due to the order that SystemVerilog header files are processed,
setting a macro in an AFU's sources file may not affect the FIM's
afu_main(). Add support for writing macros to the PIM interface
header file that afu_main() includes explicity.

Signed-off-by: Michael Adler <michael.adler@intel.com>

platforms/platmgr/tools/afu_platform_config.py

@@ -284,6 +284,13 @@ def getAfuIfc(args):
 def injectAfuIfcChanges(args, afu_ifc_db, afu_ifc_req):
     fname = afu_ifc_req['file_path']
 
+    # Allow an AFU's JSON configuration to create macros
+    if ('define' in afu_ifc_req):
+        if ('define' in afu_ifc_db):
+            afu_ifc_db['define'] += afu_ifc_req['define']
+        else:
+            afu_ifc_db['define'] = afu_ifc_req['define']
+
     if ('module-ports' not in afu_ifc_req):
         return
     if (not isinstance(afu_ifc_req['module-ports'], list)):