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 1.0 and 2.0 is
added here.

The datamanual revisions used are:
 * AM571x Silicon Revision 2.0: SPRS957D, Revised January 2017
 * AM571x Silicon Revision 1.0: SPRS919M, Revised November 2017
 * DRA71x : SPRS960B, Revised February 2017
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>