checkpatch: suspect code indent must stop at #else/#elif

When we hit and #else or #elif we know we are meeting an alternative piece
of code.  All bets are off on indent if we did not see the open of the
control so stop checking.
Signed-off-by: NAndy Whitcroft <apw@shadowen.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -1468,6 +1468,12 @@ sub process {
 			while ($cond_ptr != $cond_lines) {
 				$cond_ptr = $cond_lines;
 
+				# If we see an #else/#elif then the code
+				# is not linear.
+				if ($s =~ /^\s*\#\s*(?:else|elif)/) {
+					$check = 0;
+				}
+
 				# Ignore:
 				#  1) blank lines, they should be at 0,
 				#  2) preprocessor lines, and