mailmap: Update email address for Alexandre Belloni

Free Electrons is now Bootlin.

Link: https://lore.kernel.org/r/20191210134653.2995661-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

.mailmap

@@ -18,6 +18,7 @@ Aleksey Gorelov <aleksey_gorelov@phoenix.com>
 Aleksandar Markovic <aleksandar.markovic@mips.com> <aleksandar.markovic@imgtec.com>
 Alex Shi <alex.shi@linux.alibaba.com> <alex.shi@intel.com>
 Alex Shi <alex.shi@linux.alibaba.com> <alex.shi@linaro.org>
+Alexandre Belloni <alexandre.belloni@bootlin.com> <alexandre.belloni@free-electrons.com>
 Alexei Starovoitov <ast@kernel.org> <ast@plumgrid.com>
 Alexei Starovoitov <ast@kernel.org> <alexei.starovoitov@gmail.com>
 Alexei Starovoitov <ast@kernel.org> <ast@fb.com>