BACKPORT: UPSTREAM: perf: Fix function pointer case

With the advent of CFI it is no longer acceptible to cast function
pointers.

The robot complains thusly:

  kernel-events-core.c:warning:cast-from-int-(-)(struct-perf_cpu_pmu_context-)-to-remote_function_f-(aka-int-(-)(void-)-)-converts-to-incompatible-function-type

Bug: 287899364
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
(cherry picked from commit 1af6239d)
[cixi: Resolved minor conflict in kernel/events/core.c]
Change-Id: I37a21ece84d2566af544e5caf86d6db5bc048971
Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>