mmc: atmel-mci: change the state machine for compatibility with old IP

The state machine use in atmel-mci can't work with old IP versions
(< 0x200).  This patch allows to have a common state machine for all
versions in order to remove at91-mci driver only used for old versions.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>