arm64: cpuidle: fix #ifdef for acpi functions

The acpi_processor_ffh_lpi_* functions are defined whenever CONFIG_ACPI
is enabled, but only called and declared when CONFIG_ACPI_PROCESSOR_IDLE
is also enabled. Without that, a W=1 build triggers missing-prototope
warnings, so the #ifdef needs to be adapted:

arch/arm64/kernel/cpuidle.c:60:5: error: no previous prototype for 'acpi_processor_ffh_lpi_probe' [-Werror=missing-prototypes]
arch/arm64/kernel/cpuidle.c:65:15: error: no previous prototype for 'acpi_processor_ffh_lpi_enter' [-Werror=missing-prototypes]

Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

Author: arndb

arch/arm64/kernel/cpuidle.c

@@ -13,7 +13,7 @@
 #include <linux/of_device.h>
 #include <linux/psci.h>
 
-#ifdef CONFIG_ACPI
+#ifdef CONFIG_ACPI_PROCESSOR_IDLE
 
 #include <acpi/processor.h>