mailmap: update Guilherme G. Piccoli's email addresses

Both @canonical and @ibm email addresses are invalid now; use my personal
address instead.

Link: https://lkml.kernel.org/r/20220804202207.439427-1-gpiccoli@igalia.com


Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>