mfd: ab8500-sysctrl: Drop ancient charger

The sysctrl driver was looking for an instance of the PM2301
charger but this has been deleted from the kernel and is not
used with the U8500 systems any more. Drop the string.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20231214-ab8500-sysctrl-oneliner-v1-1-fd78a15c0b2f@linaro.org
Signed-off-by: Lee Jones <lee@kernel.org>