Fix the typo of 'suport' in kcov.h

Link: https://lkml.kernel.org/r/tencent_922CA94B789587D79FD154445D035AA19E07@qq.comSigned-off-by: NRong Tao <rongtao@cestc.cn>
Reviewed-by: NDmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>