arm_gicv3: Fix broken logic in ELRSR calculation

Fix a broken expression in the calculation of ELRSR
register bits: instead of "(lr & ICH_LR_EL2_HW) == 1"
we want to check for != 0, because the HW bit is not
bit 0 so a test for == 1 is always false.

Fixes: https://bugs.launchpad.net/bugs/1658506

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-id: 1485255993-6322-1-git-send-email-peter.maydell@linaro.org
