regulator: Fix resume from suspend to idle

When resuming from idle with the new suspend mode configuration support
we go through the resume callbacks with a state of PM_SUSPEND_TO_IDLE
which we don't have regulator constraints for, causing an error:

    dpm_run_callback(): regulator_resume_early+0x0/0x64 returns -22
    PM: Device regulator.0 failed to resume early: error -22

Avoid this and similar errors by treating missing constraints as a noop.

See also commit 57a0dd18

 ("regulator: Fix suspend to idle"),
which fixed the suspend part.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>