U-Boot for imx233-olinuxino boards

This series:
 * introduces a U-Boot package for the imx233-olinuxino boards
 * removes the bootstream generation from the kernel package
 * adds a "non-removable SD card" patchset to the kernel (required for booting from U-Boot)

Currently, U-Boot needs to be built form git://git.denx.de/u-boot-imx.git, but support for the board will probably reach the mainline version with the next release. The uboot-olinuxino-git package should become uboot-olinuxino. Please see if I got the provides= and conflicts= lines right.

Also, the version string of uboot-olinuxino-git is somewhat long and ugly, but it's the closest to the official versioning convention for U-Boot.