target-arm: Remove THUMB2EE feature from AArch64 'any' CPU

target-arm: Remove THUMB2EE feature from AArch64 'any' CPU

The AArch64 usermode 'any' CPU type was accidentally specified
with the ARM_FEATURE_THUMB2EE bit set. This is incorrect since
ARMv8 removes Thumb2EE completely. Since we never implemented
Thumb2EE anyway having the feature bit set was fairly harmless
for user-mode, but the correct thing is to not set it at all.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>