kcov: fix spelling typos in comments

Fix the typo of 'suport' in kcov.h

Link: https://lkml.kernel.org/r/tencent_922CA94B789587D79FD154445D035AA19E07@qq.com


Signed-off-by: Rong Tao <rongtao@cestc.cn>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>