This patch adds emulation for the instruction group labeled
"Floating-point <-> fixed-point conversions" in the ARM ARM.

Namely this includes the instructions SCVTF, UCVTF, FCVTZS, FCVTZU
(scalar, fixed-point).
Signed-off-by: NAlexander Graf <agraf@suse.de>
[WN: Commit message tweak, rebased, updated to new infrastructure.
 Applied bug fixes from Michael Matz and Janne Grunau.]
Signed-off-by: NWill Newton <will.newton@linaro.org>
[PMM: significant cleanup]
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <rth@twiddle.net>