ARM: at91: pm: avoid soft resetting AC DLL

Do not soft reset AC DLL as controller is buggy and this operation my
introduce glitches in the controller leading to undefined behavior.

Fixes: f0bbf179 ("ARM: at91: pm: add self-refresh support for sama7g5")
Depends-on: a02875c4 ("ARM: at91: pm: fix self-refresh for sama7g5")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221026124114.985876-2-claudiu.beznea@microchip.com