Add instruction_pointer_set() API for ia64.

Link: https://lkml.kernel.org/r/163163051195.489837.1039597819838213481.stgit@devnote2Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>