arm_gicv3_kvm: increase clroffset accordingly
    
    It forgot to increase clroffset during the loop. So it only clear the
    first 4 bytes.
    
    Fixes: 367b9f527becdd20ddf116e17a3c0c2bbc486920
    Cc: qemu-stable@nongnu.org
    Signed-off-by: Shannon Zhao <zhaoshenglong@huawei.com>
    Reviewed-by: Eric Auger <eric.auger@redhat.com>
    Message-id: 1527047633-12368-1-git-send-email-zhaoshenglong@huawei.com
    Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
    Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
    (cherry picked from commit 34ffacae085914fce54590ea84bae9c6ad95e2a4)
    Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>