Add pinmux configuration for MMC module including IODELAY
values suggested in the data manual for the various supported
modes.

IOdelay data for both silicon revision 1.1 and 2.0 is
added here.

The datamanual revisions used are:
* AM572x Silicon Revision 2.0: SPRS953B, Revised November 2016
* AM572x Silicon Revision 1.1: SPRS915R, Revised November 2016
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>