target/arm: Fix sqrt_f16 exception raising

target/arm: Fix sqrt_f16 exception raising

We are meant to explicitly pass fpst, not cpu_env.

Cc: qemu-stable@nongnu.org
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20180512003217.9105-12-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit 905edee9101c54cda5b72286b7f7607cf1c3c4d1)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>