ARM: versatile: fix board support

Versatile board is used as example to run u-boot under qemu.
The patch fixes relocation for all versatile boards and adds
a versatileqemu target to be used under qemu.

Patch tested only under qemu, not on real boards.
Tested with QEMU emulator version 0.14.50.

Signed-off-by: Stefano Babic <sbabic@denx.de>
CC: Alessandro Rubini  <rubini-list@gnudd.com>
CC: Loïc Minier <loic.minier@linaro.org>