Fix two issues in error handling in target_to_host_semarray():
* don't leak the host_array buffer if lock_user fails
* return an error if malloc() fails
v2: added missing * -Riku Voipio
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>