regulator: db8500-prcmu: Remove unused declaration power_state_active_is_enabled()

Commit 38e968380b27 ("regulators/db8500: split off shared dbx500 code")
removed this but not its declaration.

Signed-off-by: Yue Haibing <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

include/linux/regulator/db8500-prcmu.h

···
 	DB8500_NUM_REGULATORS
 };
 
-/*
- * Exported interface for CPUIdle only. This function is called with all
- * interrupts turned off.
- */
-int power_state_active_is_enabled(void);
-
 #endif