Fix cstyle warnings

This patch contains no functional changes.  It is solely intended
to resolve cstyle warnings in order to facilitate moving the spl
source code in to the zfs repository.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #681

include/linux/math64_compat.h

@@ -26,6 +26,7 @@
 #define	_SPL_MATH64_COMPAT_H
 
 #ifndef abs64
+/* CSTYLED */
 #define	abs64(x)	({ uint64_t t = (x) >> 63; ((x) ^ t) - t; })
 #endif