power: supply: cpcap-battery: use device_get_match_data() to simplify code

In the function cpcap_battery_probe(), the driver only needs the
data object, so use device_get_match_data() instead, to make the
code cleaner.

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>