spi: mxc_spi: support driver model

Add driver model support for mxc spi driver.
Most functions are restructured to be reused by DM and non-DM.
Tested on mx6slevk/mx6qsabresd board.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Reviewed-by: Stefano Babic <sbabic@denx.de>
1 file changed