simd_powerpc.h: enable FPU on FreeBSD
FreeBSD nowadays supports FPU in the kernel on powerpc*, so enable it.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Piotr Kubaj <pkubaj@FreeBSD.org>
Closes #17191