mesa/st: don't set lower_fdot in draw_nir_options

lower_fdot outputs fsum ops like fsum3, which in this stage may
go through nir_to_tgsi paths and tgsi doesn't implement them.
This hits an assert in ntt_emit_alu:

feedback: ../src/gallium/auxiliary/nir/nir_to_tgsi.c:1804:
ntt_emit_alu: Assertion `!"" "Unknown NIR opcode"' failed.

Signed-off-by: Erico Nunes <nunes.erico@gmail.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30079>

src/mesa/state_tracker/st_program.c

@@ -587,7 +587,6 @@ static const struct nir_shader_compiler_options draw_nir_options = {
    .lower_fsat = true,
    .lower_bitfield_insert = true,
    .lower_bitfield_extract = true,
-   .lower_fdot = true,
    .lower_fdph = true,
    .lower_ffma16 = true,
    .lower_ffma32 = true,