i.MX: Rework functions/types name and use new style initialization

i.MX: Rework functions/types name and use new style initialization

* use dynamic cast whenever possible
* Change function names to some more meaningful prefix
* Change type names to a more meaningful one
* use new style device initialization

Signed-off-by: Jean-Christophe DUBOIS <jcd@tribudubois.net>
Message-id: 1369898943-1993-3-git-send-email-jcd@tribudubois.net
Reviewed-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>