clocksource: hyper-v: Provide noinstr sched_clock()

clocksource: hyper-v: Provide noinstr sched_clock()

With the intent to provide local_clock_noinstr(), a variant of
local_clock() that's safe to be called from noinstr code (with the
assumption that any such code will already be non-preemptible),
prepare for things by making the Hyper-V TSC and MSR sched_clock
implementations noinstr.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Co-developed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>  # Hyper-V
Link: https://lore.kernel.org/r/20230519102715.843039089@infradead.org