x86/entry: Fix thunk function ELF sizes

Fix the following warnings:

  arch/x86/entry/thunk_64.o: warning: objtool: trace_hardirqs_on_thunk() is missing an ELF size annotation
  arch/x86/entry/thunk_64.o: warning: objtool: trace_hardirqs_off_thunk() is missing an ELF size annotation
  arch/x86/entry/thunk_64.o: warning: objtool: lockdep_sys_exit_thunk() is missing an ELF size annotation

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/89c97adc9f6cc44a0f5d03cde6d0357662938909.1563413318.git.jpoimboe@redhat.com