kprobes: Use kernel_text_address() for checking probe address

Use kernel_text_address() for checking probe address instead of
__kernel_text_address(), because __kernel_text_address() returns true
for init functions even after relaseing those functions.

That will hit a BUG() in text_poke().

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>