clk: samsung: fix sysreg save/restore when PM is enabled for CMU

clk: samsung: fix sysreg save/restore when PM is enabled for CMU

Currently, sysreg registers of a CMU that has PM and automatic clock
gating enabled are not saved / restored during runtime PM (RPM) or
s2idle. During normal suspend, they are accessed too late, after the
CMU (and potentially power domain) have been shut down, causing an
SError.

The reason is that these registers are registered to be saved/restored
via a syscore suspend handler which doesn't run during RPM or s2idle.
During normal suspend, this handler runs after the CMU has been shut
down. This registration happens as part of
samsung_clk_extended_sleep_init() via samsung_en_dyn_root_clk_gating().

When PM is enabled for a CMU, registers must be saved/restored via
exynos_arm64_cmu_suspend() / exynos_arm64_cmu_resume() respectively
instead. These use their own data structures and are unrelated to
anything that samsung_clk_extended_sleep_init() does. Calling it
unconditionally from samsung_en_dyn_root_clk_gating() therefore isn't
useful.

Update the code to prepare sysreg save / restore in a similar way to
how it handles other clock registers in the PM case already.
exynos_arm64_cmu_suspend() / exynos_arm64_cmu_resume() already handle
sysreg save/restore, just the setup was incorrect.

Fixes: 298fac4f4b96 ("clk: samsung: Implement automatic clock gating mode for CMUs")
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Link: https://patch.msgid.link/20260109-clk-samsung-autoclk-updates-v1-2-2394dcf242a9@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>