checkpatch: Fix bracing false positives on #if

789f88d0b2 only fixed #else,
fix also #if.

Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

scripts/checkpatch.pl

@@ -2539,6 +2539,7 @@ sub process {
 		}
 		if (!defined $suppress_ifbraces{$linenr - 1} &&
 					$line =~ /\b(if|while|for|else)\b/ &&
+					$line !~ /\#\s*if/ &&
 					$line !~ /\#\s*else/) {
 			my $allowed = 0;