irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d2056 ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Sebastian Andrzej Siewior <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

Author: arndb

include/linux/irqflags.h

@@ -114,7 +114,7 @@ do {						\
 # define lockdep_softirq_enter()		do { } while (0)
 # define lockdep_softirq_exit()			do { } while (0)
 # define lockdep_hrtimer_enter(__hrtimer)	false
-# define lockdep_hrtimer_exit(__context)	do { } while (0)
+# define lockdep_hrtimer_exit(__context)	do { (void)(__context); } while (0)
 # define lockdep_posixtimer_enter()		do { } while (0)
 # define lockdep_posixtimer_exit()		do { } while (0)
 # define lockdep_irq_work_enter(__work)		do { } while (0)