Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

Oops, the previous i386 version of e_fmodf.S and e_fmodl.S was
actually the amd64 version.

Add asm versions of fmod(), fmodf() and fmodl() on amd64. Add asm
versions of fmodf() amd fmodl() on i387.

fmod is similar to remainder, and the C versions are 3 to 9 times
slower than the asm versions on x86 for both, but we had the strange
mixture of all 6 variants of remainder in asm and only 1 of 6
variants of fmod in asm.