ARM: at91: pm: group constants and addresses loading

Group constants and addresses loading. This commit prepares the field for
the next one.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20210930154219.2214051-3-claudiu.beznea@microchip.com