BaseTools/Scripts/PatchCheck.py: Remove submodule false positives

BaseTools/Scripts/PatchCheck.py: Remove submodule false positives

https://bugzilla.tianocore.org/show_bug.cgi?id=2484
https://bugzilla.tianocore.org/show_bug.cgi?id=2485

Update PatchCheck to not enforce no tabs and not enforce CR/LF
line endings for .gitmodules files.  These files are updated by
git when a git submodule command is used and the updates by git
use tab characters and LF line endings.

Also update patch check to not enforce CR/LF line endings for
patch lines that create a submodule directory.  These patch
lines use LF line endings.  The git submodule directory is
added as a new file with attributes 160000 that can be detected
by looking for the pattern "new file mode 160000".

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>