samples/kprobes: print out the symbol name for the hooks

Print out the symbol name for the hooks, it makes the logs more
readable.

Link: http://lkml.kernel.org/r/1463535417-29637-2-git-send-email-shijie.huang@arm.com


Signed-off-by: Huang Shijie <shijie.huang@arm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steve Capper <steve.capper@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>