x86/kprobes: Make trampoline_handler() global and visible

This function is referenced from assembler, so in LTO
it needs to be global and visible to not be optimized away.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20190330004743.29541-7-andi@firstfloor.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>