checkpatch: notice unbalanced else braces in a patch

Patches that add or modify code like

	} else
		<foo>
or
	else {
		<bar>

where one branch appears to have a brace and the other branch does not
have a brace should emit a --strict style message.

Link: http://lkml.kernel.org/r/c6be32747fc725cbc235802991746700a0f54fdc.1486754390.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -5104,6 +5104,12 @@ sub process {
 			}
 		}
 
+# check for single line unbalanced braces
+		if ($sline =~ /.\s*\}\s*else\s*$/ ||
+		    $sline =~ /.\s*else\s*\{\s*$/) {
+			CHK("BRACES", "Unbalanced braces around else statement\n" . $herecurr);
+		}
+
 # check for unnecessary blank lines around braces
 		if (($line =~ /^.\s*}\s*$/ && $prevrawline =~ /^.\s*$/)) {
 			if (CHK("BRACES",