Doc: trace: Fix typo in coresight.txt

This patch fix spelling typos found in coresight.txt

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>