CS89x0 : add platform driver support

The CS89x0 ethernet controller is used on a number of evaluation
boards, such as the MX31ADS. The current driver has memory address and
IRQ settings for each board on which this controller is used. Driver
updates are therefore required to support other boards that also use
the CS89x0. To avoid these driver updates, a better mechanism
(platform driver support) is added to communicate the board dependent
settings to the driver.

Signed-off-by: Jaccon Bastiaansen <jaccon.bastiaansen@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>