ocfs2: constify attribute_group structures

attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with
const attribute_group. So mark the non-const structs as const.

File size before:
text data bss dec hex filename
4402 1088 38 5528 1598 fs/ocfs2/stackglue.o

File size After adding 'const':
text data bss dec hex filename
4442 1024 38 5504 1580 fs/ocfs2/stackglue.o

Link: http://lkml.kernel.org/r/cab4e59[e-mail]
Signed-off-by: Arvind Yadav <[e-mail]>
Cc: Mark Fasheh <[e-mail]>
Cc: Joel Becker <[e-mail]>
Cc: Junxiao Bi <[e-mail]>
Cc: Joseph Qi <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/ocfs2/stackglue.c

···
 	NULL,
 };
 
-static struct attribute_group ocfs2_attr_group = {
+static const struct attribute_group ocfs2_attr_group = {
 	.attrs = ocfs2_attrs,
 };