Revert "hrtimers: Force migrate away hrtimers queued after CPUHP_AP_HRTIMERS_DYING"

This reverts commit 82ac6adb which is
commit 53dac345 upstream.

It breaks the Android kernel build and can be brought back in the future
in an safe way if it is really needed.

Bug: 161946584
Change-Id: Ic3951674e27076bd9867102f525af9adc5c2a43c
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>