powerpc/imc-pmu: Add a null pointer check in update_events_in_group()

[ Upstream commit 0a233867a39078ebb0f575e2948593bbff5826b3 ]

kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure.

Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support")
Signed-off-by: Kunwu Chan <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
1 file changed