BaseTools/PatchCheck.py: Update for max length of subject and message line

BaseTools/PatchCheck.py: Update for max length of subject and message line

This patch update PatchCheck.py:
1. The subject line of the commit message should be < 72 characters.
2. The other lines of the commit message should be < 76 characters.

Fixes: https://bugzilla.tianocore.org/show_bug.cgi?id=113
Cc: Liming Gao <liming.gao@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>