hrtimer: Make room in 'struct hrtimer_cpu_base'

The upcoming softirq based hrtimers support requires an additional field in
the hrtimer_cpu_base struct, which would grow the struct size beyond a
cache line.

The hrtimer_cpu_base::nr_retries and ::nr_hangs members are solely
used for diagnostic output and have no requirement to be 'unsigned int'.

Make them 'unsigned short' to create room for the new struct member.

No functional change.

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@chromium.org
Link: http://lkml.kernel.org/r/20171221104205.7269-13-anna-maria@linutronix.de


Signed-off-by: Ingo Molnar <mingo@kernel.org>