[AArch64][SVE] Replace fmul, fadd and fsub LLVM IR instrinsics with LLVM IR binary ops

Replacing fmul and fadd instrinsics with their binary ops results
more succinct AArch64 SVE output, e.g.:

4:   65428041 	fmul	z1.h, p0/m, z1.h, z2.h
8:   65408020 	fadd	z0.h, p0/m, z0.h, z1.h
->
4:   65620020   fmla    z0.h, p0/m, z1.h, z2.h