ARM: OMAP2+: Fix eMMC on n900 with device tree

Looks like we need to configure the regulators and use the pdata
quirk to make eMMC work with device tree.

It seems that mostly vaux3 is used, and only some earlier revisions
used vmmc2. This has been tested to work on devices where the
system_rev passed by the bootloader has versions 0x0010, 0x2101
and 0x2204.

Cc: devicetree@vger.kernel.org
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Sebastian Reichel <sre@debian.org>
[tony@atomide.com: updated with pinctrl changes and comments from Sebastian]
Signed-off-by: Tony Lindgren <tony@atomide.com>