x86/alternatives: Print containing function

... in the "debug-alternative" output so that one can find her way
easier when staring at the vmlinux disassembly.

For example:

  apply_alternatives: feat: 3*32+18, old: (read_tsc+0x0/0x10 (ffffffff8101d1c0) len: 5), repl: (ffffffff824e6d33, len: 5)
  					   ^^^^^^^^^^^^^^^^^
  ffffffff8101d1c0: old_insn: 0f 31 90 90 90
  ffffffff824e6d33: rpl_insn: 0f ae e8 0f 31
  ffffffff8101d1c0: final_insn: 0f ae e8 0f 31

No functional changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: X86 ML <x86@kernel.org>
Link: https://lkml.kernel.org/r/20181211222326.14581-3-bp@alien8.de

arch/x86/kernel/alternative.c

@@ -393,10 +393,10 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 			continue;
 		}
 
-		DPRINTK("feat: %d*32+%d, old: (%px len: %d), repl: (%px, len: %d), pad: %d",
+		DPRINTK("feat: %d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d), pad: %d",
 			a->cpuid >> 5,
 			a->cpuid & 0x1f,
-			instr, a->instrlen,
+			instr, instr, a->instrlen,
 			replacement, a->replacementlen, a->padlen);
 
 		DUMP_BYTES(instr, a->instrlen, "%px: old_insn: ", instr);