perf arm-spe: Fix a typo in comment

mainline inclusion
from mainline-v5.11-rc1
commit 903b6594
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4NGPV


CVE: NA

-------------------------------------------------

Fix a typo: s/iff/if.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20201111071149.815-3-leo.yan@linaro.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Wei Li <liwei391@huawei.com>
Reviewed-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>