mmc: omap_hsmmc: Add support to get pinctrl values and max frequency for different hw revisions

AM572x SR1.1 requires different IODelay values to be used than that used
in AM572x SR2.0. These values are populated in device tree. Add
capability in omap_hsmmc driver to extract IOdelay values for different
silicon revision. The maximum frequency is also reduced when using a ES1.1.
To keep the ability to boot both revsions with the same dtb, those values
can be provided by the platform code.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>