power: qpnp-smbcharger: use correct bits for APSD results

The charger chip does automatic power source detection upon USB
insertion. The USB type is then reported to the USB driver for further
enumeration/action. However, there is a problem in the charger driver
right now where it detects a normal USB device as an ACA device. This
is due to the driver following an older version of the documentation
where ACA devices were used in the lower bits instead of FMB USB and
UART status.

Fix this by only using the upper 4 bits of the IDEV_STS for USB type
detection.

Change-Id: I66ba59406879737b12643c5f6cc1d93d1eedce70
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>