accel/tcg: Hoist first page lookup above pointer_wrap

accel/tcg: Hoist first page lookup above pointer_wrap

For strict alignment targets we registered cpu_pointer_wrap_notreached,
but generic code used it before recognizing the alignment exception.
Hoist the first page lookup, so that the alignment exception happens first.

Cc: qemu-stable@nongnu.org
Buglink: https://bugs.debian.org/1112285
Fixes: a4027ed7d4be ("target: Use cpu_pointer_wrap_notreached for strict align targets")
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>