mfd: twl-core: Clean up module by removing twl603x pdata handling

Since currently nobody uses TWL603x platform data and all new
users will supply it through device tree, handling of these
data within twl-core will never be used, so remove it.

Signed-off-by: Ruslan Ruslichenko <ruslan.ruslichenko@globallogic.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>