target/sparc: Add FQ and FSR.QNE

target/sparc: Add FQ and FSR.QNE

Add support for, and migrate, a single-entry fp
instruction queue for sparc32.

Signed-off-by: Carl Hauser <chauser@pullman.com>
[rth: Split from a larger patch;
      adjust representation with union;
      add migration state]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: Carl Hauser <chauser@pullman.com>