BaseTools/PatchCheck.py: Skip length check for user name in xxx-by

BaseTools/PatchCheck.py: Skip length check for user name in xxx-by

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2836
Current PatchCheck.py checks each line to ensure line's length is not
larger than 76. But there's a case that length of user's name is much
longer than that number. So enhance the script to handle this case.

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
Reviewed-by: Yuwei Chen<yuwei.chen@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>