x86/mce/therm_throt: Mark throttle_active_work() as __maybe_unused

throttle_active_work() is only called if CONFIG_SYSFS is set, otherwise
we get a harmless warning:

  arch/x86/kernel/cpu/mce/therm_throt.c:238:13: error: 'throttle_active_work' \
	  defined but not used [-Werror=unused-function]

Mark the function as __maybe_unused to avoid the warning.

Fixes: f6656208 ("x86/mce/therm_throt: Optimize notifications of thermal throttle")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: bberg@redhat.com
Cc: ckellner@redhat.com
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: hdegoede@redhat.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191210203925.3119091-1-arnd@arndb.de

arch/x86/kernel/cpu/mce/therm_throt.c

@@ -235,7 +235,7 @@ static void get_therm_status(int level, bool *proc_hot, u8 *temp)
 	*temp = (msr_val >> 16) & 0x7F;
 }
 
-static void throttle_active_work(struct work_struct *work)
+static void __maybe_unused throttle_active_work(struct work_struct *work)
 {
 	struct _thermal_state *state = container_of(to_delayed_work(work),
 						struct _thermal_state, therm_work);