mailmap: Update email address for Gregory CLEMENT

As now Free Electrons is Bootlin.
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

.mailmap

@@ -62,6 +62,7 @@ Frank Zago <fzago@systemfabricworks.com>
 Greg Kroah-Hartman <greg@echidna.(none)>
 Greg Kroah-Hartman <gregkh@suse.de>
 Greg Kroah-Hartman <greg@kroah.com>
+Gregory CLEMENT <gregory.clement@bootlin.com> <gregory.clement@free-electrons.com>
 Henk Vergonet <Henk.Vergonet@gmail.com>
 Henrik Kretzschmar <henne@nachtwindheim.de>
 Henrik Rydberg <rydberg@bitmath.org>