arm64: fix typos in comments

Various spelling mistakes in comments.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Link: https://lore.kernel.org/r/20220318103729.157574-10-Julia.Lawall@inria.fr


[will: Squashed in 20220318103729.157574-28-Julia.Lawall@inria.fr]
Signed-off-by: Will Deacon <will@kernel.org>