checkpatch: emit an error on formats with 0x%<decimal>

Using 0x%d is wrong.  Emit a message when it happens.

Miscellanea:

Improve the %Lu warning to match formats like %16Lu.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -4816,16 +4816,20 @@ sub process {
 			     "Consecutive strings are generally better as a single string\n" . $herecurr);
 		}
 
-# check for %L{u,d,i} in strings
+# check for %L{u,d,i} and 0x%[udi] in strings
 		my $string;
 		while ($line =~ /(?:^|")([X\t]*)(?:"|$)/g) {
 			$string = substr($rawline, $-[1], $+[1] - $-[1]);
 			$string =~ s/%%/__/g;
-			if ($string =~ /(?<!%)%L[udi]/) {
+			if ($string =~ /(?<!%)%[\*\d\.\$]*L[udi]/) {
 				WARN("PRINTF_L",
 				     "\%Ld/%Lu are not-standard C, use %lld/%llu\n" . $herecurr);
 				last;
 			}
+			if ($string =~ /0x%[\*\d\.\$\Llzth]*[udi]/) {
+				ERROR("PRINTF_0xDECIMAL",
+				      "Prefixing 0x with decimal output is defective\n" . $herecurr);
+			}
 		}
 
 # check for line continuations in quoted strings with odd counts of "