r8152: adjust usb_autopm_xxx

Add usb_autopm_xxx for rtl8152_get_settings() ,and remove
usb_autopm_xxx from read_mii_word() and write_mii_word().

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