BaseTools/PatchCheck: Add copy from/to keywords

https://bugzilla.tianocore.org/show_bug.cgi?id=2044

When files are very similar, git will copy an existing
file to a new location and then apply differences.  This
is operation identified in the diff with 'copy from' and
'copy to' lines that need to be ignored.

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

BaseTools/Scripts/PatchCheck.py

@@ -331,6 +331,8 @@ class GitDiffCheck:
         'old mode ',
         'new mode ',
         'similarity index ',
+        'copy from ',
+        'copy to ',
         'rename ',
         )