BaseTools: Update SetupGit.py to add new 'fp' alias for patch formatting

To help people format patches with the correct options, add an alias
named 'fp' to SetupGit.py that runs format-patch with '-M --stat=1000
--stat-graph-width=20'.

Signed-off-by: Rebecca Cran <rebecca@bsdio.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>