nir: Add nir_lower_fdot_instruction nir pass
What does this MR do and why?
nir: Add nir_lower_fdot_instruction nir pass
nir_compiler_options for svga allow fdot instruction. Thus, when
we try to generate vertex shader in draw_llvm path, shaders can have
fdot instructions. Such shaders causes assert in lp_build_nir_soa()
due to fdot instructions not supported in llvm path.
This patch is adding nir_lower_fdot_instruction pass and which will
be called in lp_build_nir_prepasses to lower fdot instructions
Fixes crash seen with topogun-1.06-orc-84k-resize.trace in internal
testing