x86/tools: insn_decoder_test.c: Emit standard build success messages

The standard 'success' output of insn_decoder_test spams build logs with:

  arch/x86/tools/insn_decoder_test: success: Decoded and checked 8258521 instructions

Prefix the message with the standard '  ' (two spaces) used by kbuild to denote
regular build messages, making it easier for tools to filter out
warnings and errors.

Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Jürgen Groß <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Michal Marek <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Vitaly Kuznetsov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Ingo Molnar

arch/x86/tools/insn_decoder_test.c

@@ -167,7 +167,7 @@ int main(int argc, char **argv)
 		pr_warn("Decoded and checked %d instructions with %d "
 			"failures\n", insns, warnings);
 	else
-		fprintf(stdout, "%s: success: Decoded and checked %d"
+		fprintf(stdout, "  %s: success: Decoded and checked %d"
 			" instructions\n", prog, insns);
 	return 0;
 }