hw/mips/malta: Fix the malta machine on big endian hosts

hw/mips/malta: Fix the malta machine on big endian hosts

Booting a Linux kernel with the malta machine is currently broken
on big endian hosts. The cpu_to_gt32 macro wants to byteswap a value
for little endian targets only, but uses the wrong way to do this:
cpu_to_[lb]e32 works the other way round on big endian hosts! Fix
it by using the same ways on both, big and little endian hosts.

Fixes: 0c8427baf0 ("hw/mips/malta: Use bootloader helper to set BAR registers")
Cc: qemu-stable@nongnu.org
Message-Id: <20230330152613.232082-1-thuth@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>