HID: nvidia-shield: Select POWER_SUPPLY Kconfig option

Battery information reported by the driver depends on the power supply
subsystem. Select the required subsystem when the HID_NVIDIA_SHIELD Kconfig
option is enabled.

Fixes: 3ab196f8 ("HID: nvidia-shield: Add battery support for Thunderstrike")
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>