ab8500-charger: Use USBLink1Status Register

The newer AB's such as the AB8505, AB9540 etc include a
USBLink1 Status register which detects a larger range of
external devices. This should be used instead of the
USBLine Status register.

Signed-off-by: Marcus Cooper <marcus.xm.cooper@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Hakan BERG <hakan.berg@stericsson.com>
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>
Tested-by: Yang QU <yang.qu@stericsson.com>