[oe] Bulding multiple U-Boot configs for one machine

[Ulf Samuelsson]

Managed to get some time over and checked in a recipe
for u-boot-2010.12 which builds all u-boot configs
specified in the UBOOT_MACHINES (note "S" at the end)

The frecipe is available in a private branch:
  "ulf/linux-2.6.30-2011-01-16"  (or similar).

There is a SAM9M10 machine checked in as well as a test case.
grep for UBOOT_MACHINES in the conf/machine directory to find out which.

Note that
UBOOT_MACHINE = "at91sam9m10g45ek_config"

but

UBOOT_MACHINES = "at91sam9m10g45ek_dataflash at91sam9m10g45ek_sd"

I.E: No "_config" in the list.

The goal of the new branch is to test booting from an SD-Card
without any other flash in the system.
Have tested this outside openembedded so far, but
the current branch is still to be tested on a board.

Best Regards
Ulf Samuelsson