When %gs cannot be used, we use register offset addressing.
This path is almost never used, so it was clearly not tested.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200406174803.8192-1-richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>