target/arm: Free TCG temps in trans_VMOV_64_sp()

The function neon_store_reg32() doesn't free the TCG temp that it
is passed, so the caller must do that. We got this right in most
places but forgot to free the TCG temps in trans_VMOV_64_sp().

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190827121931.26836-1-peter.maydell@linaro.org