staging: lustre: include: linux: libcfs: use __packed instead of __attribute__((packed))

This patch fixes checpatch.pl warning in libcfs_debug.h file.
WARNING: __packed is preferred over __attribute__((packed))
Signed-off-by: Tapasweni Pathak <tapaswenipathak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/include/linux/libcfs/libcfs_debug.h

@@ -80,7 +80,7 @@ struct ptldebug_header {
 	__u32 ph_pid;
 	__u32 ph_extern_pid;
 	__u32 ph_line_num;
-} __attribute__((packed));
+} __packed;
 
 #define PH_FLAG_FIRST_RECORD 1