ACPI / sleep: Drop acpi_suspend() which is not used

The acpi_suspend() function has no callers, so drop it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>

drivers/acpi/sleep.h

@@ -1,6 +1,4 @@
 
-extern int acpi_suspend(u32 state);
-
 extern void acpi_enable_wakeup_devices(u8 sleep_state);
 extern void acpi_disable_wakeup_devices(u8 sleep_state);