OMAP 4 SPL support at U-Boot

[asac, Jul 24, 2011]: please update work items etc. and drop comments to blueprints as part of your weekly standard work flow; if a blueprint moves it should be visible here; if its blocked, this should be communicated clearly here either
[rsalveti, Jul 26, 2011]: unable to integrate in 11.07 timeframe as we were blocked by upstream. Moving it to 11.08.
[rsalveti, Aug 10, 2011]: John, please let me know if you think you're unable to make it for 11.08, or if you're blocked by something again.
[jcrigby, Aug 10, 2011]: Current upstream with SPL works for booting a kernel. However USB Host on Panda no longer works.
[rsalveti, Aug 19, 2011]: The board doesn't work with X-Loader anymore if u-boot was built with SPL, so to use the newer u-boot you also need to replace your MLO.
[rsalveti, Aug 31, 2011]: Besides changing u-boot.bin to u-boot.img everything worked well and it was properly integrated at the omap4 based hwpacks.

Headline: Pandaboard hwpacks now have support for U-Boot SPL, dropping X-Loader.
Acceptance: Pandaboard hwpack delivers SPL and U-Boot, is able to boot with the LEB image working the same way as when booting with X-Loader, without any regression.

Work items:
Build and test the existing omap4 spl support found on omapzoom on panda: DONE
Integrate existing spl support as is into u-boot-linaro-next git tree: DONE
Once spl patch series is approved for upstream pull those patches into u-boot-linaro-stable and push a packaged version to archive: DONE
[rsalveti] Change panda hwpacks to remove x-loader: DONE
[rsalveti] Change linaro-image-create to support u-boot.img instead of u-boot.bin: DONE
Test if the image behave the same way with and without SPL: DONE
Test if u-boot is still able to boot with x-loader on Panda (not able anymore, SPL is now a requirement): DONE