[Gta04-owner] ext4 support in U-Boot added

[Dr. H. Nikolaus Schaller]

it took a while but now I have added ext4 support to U-Boot.
There are new 'ext4ls' and 'ext4load' commands that work like their ext2 counterparts.

And there is a 'ls' and 'load' command that tries to find out automatically which type the partition i.

I.e. on the standard hw-validation partitioning scheme:

ls mmc 0:1 /    -- will list a FAT partition
ls mmc 0:2 /    -- will list an ext* partition

mmc rescan 0 appears to be required to load the partition table.

mmc part 0 lists the partitions.

I have also modified the boot.scr so that it uses the new, more generic 'load' command.

This now allows to place the uImage either in / or /boot - either in a FAT or an ext2,3,4 partition.
The same for bootargs.scr.

There is only one known issue: the PARTITIONTYPE is reported to be FAT if the uImage/bootargs.scr
is found in the root directory and EXT if it is found in /boot. This is not correct but I don't see a
solution. It may be better to remove that completely since the kernel is also able to auto-detect
(some) partition types.

The uboot.bin and uboot.flash and boot.scr can be found here:

	http://download.goldelico.com/gta04/unstable/

Please report issues asap, so that I can make an official release out of it.

Nikolaus