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 57a0dd187956ea04 ("regulator: Fix suspend to idle"),
which fixed the suspend part.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/core.c

···
 
 	rstate = regulator_get_suspend_state(rdev, *state);
 	if (rstate == NULL)
-		return -EINVAL;
+		return 0;
 
 	mutex_lock(&rdev->mutex);