misc: Add attribute groups

Add groups field to struct miscdevice for passing the attribute groups
at device creation.  In this way, the driver can avoid the manual call
of device_create_file() after the device registration, which is
basically a racy operation, in addition to the reduction of manual
device_remove_file() calls.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/miscdevice.h

@@ -52,6 +52,7 @@
 #define MISC_DYNAMIC_MINOR	255
 
 struct device;
+struct attribute_group;
 
 struct miscdevice  {
 	int minor;
@@ -60,6 +61,7 @@ struct miscdevice  {
 	struct list_head list;
 	struct device *parent;
 	struct device *this_device;
+	const struct attribute_group **groups;
 	const char *nodename;
 	umode_t mode;
 };