checkpatch.pl: Add 'debug' to the list of logFunctions

While the kernel mainly uses pr_debug(...), etc, for debug messages, we
use debug(...).  Add this to the list of logFunctions so that they are
correctly checked (and not warned against) for long string literals.

Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/tools/checkpatch.pl b/tools/checkpatch.pl
index 051ba0d..9f23901 100755
--- a/tools/checkpatch.pl
+++ b/tools/checkpatch.pl
@@ -272,6 +272,7 @@
 	[a-z0-9]+_(?:printk|emerg|alert|crit|err|warning|warn|notice|info|debug|dbg|vdbg|devel|cont|WARN)(?:_ratelimited|_once|)|
 	WARN(?:_RATELIMIT|_ONCE|)|
 	panic|
+	debug|
 	MODULE_[A-Z_]+
 )};