target-arm/translate-a64.c: Fix dead ?: in handle_simd_shift_fpint_conv()

target-arm/translate-a64.c: Fix dead ?: in handle_simd_shift_fpint_conv()

In handle_simd_shift_fpint_conv(), the combination of is_double == true,
is_scalar == false and is_q == false is an unallocated encoding; the
'both parts false' case of the nested ?: expression for calculating
maxpass is therefore unreachable and can be removed.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: 1402171881-14343-4-git-send-email-peter.maydell@linaro.org