cputlb: use uint64_t for interim values for unaligned load

When running on 32 bit TCG backends a wide unaligned load ends up
truncating data before returning to the guest. We specifically have
the return type as uint64_t to avoid any premature truncation so we
should use the same for the interim types.

Fixes: https://bugs.launchpad.net/qemu/+bug/1830872


Fixes: eed56642

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>

accel/tcg/cputlb.c

@@ -1315,7 +1315,7 @@ load_helper(CPUArchState *env, target_ulong addr, TCGMemOpIdx oi,
         && unlikely((addr & ~TARGET_PAGE_MASK) + size - 1
                     >= TARGET_PAGE_SIZE)) {
         target_ulong addr1, addr2;
-        tcg_target_ulong r1, r2;
+        uint64_t r1, r2;
         unsigned shift;
     do_unaligned_access:
         addr1 = addr & ~(size - 1);