[BLUETOOTH]: Make hidp_setup_input() return int

This patch:
- makes hidp_setup_input() return int to indicate errors;
- checks its return value to handle errors.

And this time it is against -rc7-mm1 tree.

Thanks to roel and Marcel Holtmann for comments.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: David S. Miller <davem@davemloft.net>