target/arm: Use FPST_F16 for SME FMOPA (widening)

target/arm: Use FPST_F16 for SME FMOPA (widening)

This operation has float16 inputs and thus must use
the FZ16 control not the FZ control.

Cc: qemu-stable@nongnu.org
Fixes: 3916841ac75 ("target/arm: Implement FMOPA, FMOPS (widening)")
Reported-by: Daniyal Khan <danikhan632@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20240717060149.204788-3-richard.henderson@linaro.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2374
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit 207d30b5fdb5b45a36f26eefcf52fe2c1714dd4f)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>