xtensa: add static function tracer support

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

diff --cc arch/xtensa/Kconfig
Simple merge

diff --cc arch/xtensa/boot/lib/Makefile
Simple merge

diff --cc arch/xtensa/include/asm/ftrace.h
Simple merge

diff --cc arch/xtensa/kernel/Makefile
Simple merge

diff --cc arch/xtensa/kernel/mcount.S
Simple merge

diff --cc arch/xtensa/kernel/xtensa_ksyms.c
Simple merge