uImage: only try to load 'kernel' images (Hollis Blanchard)

Loading other image types (e.g. IH_TYPE_MULTI, IH_TYPE_FLATDT) is not
implemented.

IH_TYPE_STANDALONE images could be loaded, but would unexpectedly fail if they
tried to use any uboot services.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5765 c046a42c-6fe2-441c-8c8c-71466251a162
