It is read-only constant structure, so properly mark it with const keyword.

Link: https://lore.kernel.org/r/20220104153529.31647-3-pali@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Acked-by: NThomas Petazzoni <thomas.petazzoni@bootlin.com>