power: supply: act8945a: correct kerneldoc

Remove incorrect kerneldoc marker to fix W=1 warning:

  drivers/power/supply/act8945a_charger.c:22: warning:
    This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>