r8152: fix runtime function for RTL8152

The RTL8152 doesn't have U1U2 and U2P3 features, so use different
runtime functions for RTL812 and RTL8153 by adding autosuspend_en()
to rtl_ops.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>