Revert "dm: ns16550: Add support for reg-offset property"

Revert "dm: ns16550: Add support for reg-offset property"

This reverts commit d9a3bec682f9756621615f4306718a356a3230e3.

While this is a correct change to do long term it unfortunately breaks a
number of platforms that are using pdata and not named struct members so
they are getting all of their data after 'base' incorrect.

Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tom Rini <trini@konsulko.com>