regulator: ab8500: Also check for AB8505 based platforms

Ensure we initialise AB8505 external supply regulators.

Signed-off-by: Alexandre Torgue <alexandre.torgue@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Philippe LANGLAIS <philippe.langlais@stericsson.com>
Tested-by: Xiao Mei ZHANG <xiaomei.zhang@stericsson.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>