xattr: Remove unnecessary NULL attribute name check

When NULL is passed to one of the xattr system calls as the attribute
name, copying that name from user space already fails with -EFAULT;
xattr_resolve_name is never called with a NULL attribute name.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/xattr.c

@@ -675,9 +675,6 @@ xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
 {
 	const struct xattr_handler *handler;
 
-	if (!*name)
-		return ERR_PTR(-EINVAL);
-
 	for_each_xattr_handler(handlers, handler) {
 		const char *n;