jffs2: move jffs2_xattr_handlers to .rodata

This makes it harder for accidental or malicious changes to
jffs2_xattr_handlers at runtime.

Cc: David Woodhouse <[e-mail]>
Cc: Richard Weinberger <[e-mail]>
Cc: [e-mail]
Signed-off-by: Wedson Almeida Filho <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Zhihao Cheng <[e-mail]>
Signed-off-by: Christian Brauner <[e-mail]>

fs/jffs2/xattr.c

···
  * do_jffs2_setxattr(inode, xprefix, xname, buffer, size, flags)
  *   is an implementation of setxattr handler on jffs2.
  * -------------------------------------------------- */
-const struct xattr_handler *jffs2_xattr_handlers[] = {
+const struct xattr_handler * const jffs2_xattr_handlers[] = {
 	&jffs2_user_xattr_handler,
 #ifdef CONFIG_JFFS2_FS_SECURITY
 	&jffs2_security_xattr_handler,

fs/jffs2/xattr.h

···
 extern int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
 			     const char *buffer, size_t size, int flags);
 
-extern const struct xattr_handler *jffs2_xattr_handlers[];
+extern const struct xattr_handler * const jffs2_xattr_handlers[];
 extern const struct xattr_handler jffs2_user_xattr_handler;
 extern const struct xattr_handler jffs2_trusted_xattr_handler;