UPSTREAM: timer: Export destroy_hrtimer_on_stack()

hrtimer_init_on_stack() needs a matching call to
destroy_hrtimer_on_stack(), so both need to be exported.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit c08376ac)
[astrachan: Fixes {i386,amd64}-allmodconfig build failure in vsoc.ko
 noticed by kernelci.org project building kernel/common]
Bug: 79376877
Change-Id: If4d5c466255019322ea21ef38ee5b1b382cce969
Signed-off-by: Alistair Strachan <astrachan@google.com>