selftests/ftrace: make kprobe profile testcase description unique

selftests/ftrace: make kprobe profile testcase description unique

Commit 32f6e5da83c7 ("selftests/ftrace: Add kprobe profile testcase")
added a new kprobes testcase, but has a description which does not
describe what the test case is doing and is duplicating the description
of another test case.

Therefore change the test case description, so it is unique and then
allows easily to tell which test case actually passed or failed.

Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>