target/arm: Ignore HCR_EL2.ATA when {E2H,TGE} != 11

Unlike many other bits in HCR_EL2, the description for this
bit does not contain the phrase "if ... this field behaves
as 0 for all purposes other than", so do not squash the bit
in arm_hcr_el2_eff.

Instead, replicate the E2H+TGE test in the two places that
require it.

Reported-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Message-id: 20201008162155.161886-4-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>