perf: Fix HW/SW event grouping failure

In commit b05ec5a7 ("perf: Skip permission checks on kernel owned
perf events"), the patch changes the first argument of
find_get_context() from pmu to event. This leads to
group_leader != ctx so that hardware events and software
events can not be grouped together.

Bug: 30675453
Test: LTP syscalls-perf_event_open02 and set hwmon governor

CRs-Fixed: 2270895
Change-Id: I0b0021aab873f0886a7028a0a14637702b62b3d4
Git-repo: https://source.codeaurora.org/quic/la/kernel/common/


Git-commit: 03aba81b63d0c6c36bfa5a66b61956a1e480bd43
Signed-off-by: Wei Wang <wvw@google.com>
Signed-off-by: Chetan C R <cravin@codeaurora.org>