MAINTAINERS: Update Bjorn's email address

Update the email address for Bjorn's maintainer entries and fill in
.mailmap accordingly.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220819142549.1605081-1-bjorn.andersson@linaro.org