clocksource: Use GENMASK_ULL in definition of CLOCKSOURCE_MASK

commit 0773cea37470f8e080c510fe720fc356cf35df3a upstream

Besides reusing existing code this removes the special case handling
for 64-bit masks, which causes clang to raise a shift count overflow
warning due to https://bugs.llvm.org//show_bug.cgi?id=10030

.

Suggested-by: Dmitry Torokhov <dtor@chromium.org>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Cc: Grant Grundler <grundler@chromium.org>
Cc: Greg Hackmann <ghackmann@google.com>
Cc: Michael Davidson <md@google.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170418233037.70990-1-mka@chromium.org


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[nc: cycle_t wasn't eliminated until commit a5a1d1c2914b ("clocksource:
     Use a plain u64 instead of cycle_t") in v4.10]
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>