Revert "nir: replace lower_ffma and fuse_ffma with has_ffma"

This reverts commit 939ddf3f67.

Intel has a separate pass for fusing FFMAs selectively.  We split
these flags in commit 1b72c31e1f and
the reasoning still stands.  The patch being reverted was just a
cleanup, so there should be no issue with reverting it.

Acked-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6849>

src/broadcom/compiler/nir_to_vir.c

@@ -2874,6 +2874,9 @@ const nir_shader_compiler_options v3d_nir_options = {
         .lower_unpack_half_2x16 = true,
         .lower_fdiv = true,
         .lower_find_lsb = true,
+	.lower_ffma16 = true,
+	.lower_ffma32 = true,
+	.lower_ffma64 = true,
         .lower_flrp32 = true,
         .lower_fpow = true,
         .lower_fsat = true,