pan/bi: Print blend descriptor source properly

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7206>
diff --git a/src/panfrost/bifrost/bi_print.c b/src/panfrost/bifrost/bi_print.c
index dbacdce..00644cc 100644
--- a/src/panfrost/bifrost/bi_print.c
+++ b/src/panfrost/bifrost/bi_print.c
@@ -109,6 +109,9 @@
                 fprintf(fp, "#0x%" PRIx64, bi_get_immediate(ins, s));
         else if (index & BIR_INDEX_ZERO)
                 fprintf(fp, "#0");
+        else if (index & BIR_INDEX_BLEND)
+                fprintf(fp, "blend_descriptor_%u.%c", ins->blend_location,
+                        (index & ~BIR_INDEX_BLEND) == BIFROST_SRC_FAU_HI ? 'y' : 'x');
         else
                 fprintf(fp, "#err");
 }