hw/xtensa/xtfpga: treat uImage load address as virtual

hw/xtensa/xtfpga: treat uImage load address as virtual

U-boot for xtensa always treats uImage load address as virtual address.
This is important when booting uImage on xtensa core with MMUv2, because
MMUv2 has fixed non-identity virtual-to-physical mapping after reset.

Always do virtual-to-physical translation of uImage load address and
load uImage at the translated address. This fixes booting uImage kernels
on dc232b and other MMUv2 cores.

Cc: qemu-stable@nongnu.org
Reported-by: Waldemar Brodkorb <mail@waldemar-brodkorb.de>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>