checkpatch: avoid "spaces required around that ':'" false positive

Since commit 1f65f94 ("checkpatch: add checks for question mark and
colon spacing") back in 2008, checkpatch has reported false positive for
asm volatile uses of "::" checkpatch thinks colons should always have
spaces around it.

Add an exception for colons with colons on either side for this valid asm
volatile (and c++) use.

Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Yehuda Yitschak <yehuday@marvell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -3845,6 +3845,14 @@ sub process {
 					    	$ok = 1;
 					}
 
+					# for asm volatile statements
+					# ignore a colon with another
+					# colon immediately before or after
+					if (($op eq ':') &&
+					    ($ca =~ /:$/ || $cc =~ /^:/)) {
+						$ok = 1;
+					}
+
 					# messages are ERROR, but ?: are CHK
 					if ($ok == 0) {
 						my $msg_type = \&ERROR;