BaseTools: trim warning to error

As the error is changed to warning, Trim.py will skip the build
error when the source code have exactly issue.
This patch change warning to error to opens the checking.

Cc: Rebecca Cran <rebecca@bsdio.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Bob Feng <bob.c.feng@intel.com>
Signed-off-by: Yuwei Chen <yuwei.chen@intel.com>
Reviewed-by: Rebecca Cran <rebecca@bsdio.com>

BaseTools/Source/Python/Trim/Trim.py

@@ -281,10 +281,10 @@ def DoInclude(Source, Indent='', IncludePathList=[], LocalSearchPath=None, Inclu
                         F = File.readlines()
                 break
         else:
-            EdkLogger.warn("Trim", "Failed to find include file %s" % Source)
+            EdkLogger.error("Trim", "Failed to find include file %s" % Source)
             return []
     except:
-        EdkLogger.warn("Trim", FILE_OPEN_FAILURE, ExtraData=Source)
+        EdkLogger.error("Trim", FILE_OPEN_FAILURE, ExtraData=Source)
         return []