linux: add a patch to set DSS pins in correct mux mode.

Latest U-Boot only sets the mux pins of the pheriperal that are
needed to boot the kernel, so now is the kernel responsability
to set all the remaining mux pads.

Add a patch from Enric Balletbo to setup the DSS pin muxes
correctly and enable display functionality.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
linux: igep00x0: built-in TFP410 support instead of as a module

Since the TFP410 DPI-to-DVI chip is used to display video on
IGEP boards and the igep00x0 defconfig is only used for these
devices, it is better to have it built in the kernel instead
than as a module.

Also, configure to have only one overlay instead of the maximum
three, since there is an bug in latest Xorg server that configures
the remaining overlay buffes with paddr equal to zero.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Merge pull request #15 from martinezjavier/master-next

linux: add a patch to set DSS pins in correct mux mode.
linux: igep00x0: built-in TFP410 support instead of as a module