This adds a omap_set_bootmmc_devname function which can be used
to specify the MMC boot device. In an xload configuration this
is then used to load the next stage. In a regular build this is
used to mount /boot.
Also a device_detect_by_name is added to allow to disable probing
for sd/mmc cards during startup.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Jan Luebbe <jlu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Folded fix into this patch:

[PATCH] omap4 regression: set correct boot source

Signed-off-by: Vicente Bergas <vicencb@gmail.com>

Make loading environment from MMC generic for all OMAP.

Tested on AM335x, OMAP4.

Signed-off-by: Teresa Gámez <t.gamez@phytec.de>
Tested-by: Jan Weitzel <j.weitzel@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

The bootsource functions are not specific to the first stage
bootloader. They may also be used for detecting the
bootsource to decide where to load the environment from.

Also clean up includes in board files.

Signed-off-by: Teresa Gámez <t.gamez@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>