power: supply: cpcap-battery: improve handling of 3rd party batteries.

Adds a module option to ignore a missing temperature sensor.
Useful for 3rd party batteries.

Signed-off-by: Carl Philipp Klemm <carl@uvos.xyz>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>