mfd: da9063: Remove platform_data support

There are no in-kernel users anymore, so remove this outdated interface.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Steve Twiss <stwiss.opensource@diasemi.com>
Tested-by: Steve Twiss <stwiss.opensource@diasemi.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Lee Jones <lee.jones@linaro.org>