[PATCH] ASoC: SOF: amd: Fix build error with built-in config

[Takashi Iwai <tiwai@xxxxxxx>]

Makefile in AMD ACP driver has a line substitution with "=" instead of
"+="; this overrides the preexisting item, hence it broke the build
after the recent change to replace *-objs with *-y.

This patch corrects the line.

Fixes: 1a74b21ce59f ("ASoC: SOF: amd: Add Probe functionality support for amd platforms.")
Fixes: 9c2f5b6eb8b7 ("ASoC: SOF: Use *-y instead of *-objs in Makefile")
Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Closes: https://lore.kernel.org/r/20240510170305.03b67d9f@xxxxxxxxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
 sound/soc/sof/amd/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/sof/amd/Makefile b/sound/soc/sof/amd/Makefile
index 380a9769c321..d1424c09172d 100644
--- a/sound/soc/sof/amd/Makefile
+++ b/sound/soc/sof/amd/Makefile
@@ -5,7 +5,7 @@
 # Copyright(c) 2021, 2023 Advanced Micro Devices, Inc. All rights reserved.
 
 snd-sof-amd-acp-y := acp.o acp-loader.o acp-ipc.o acp-pcm.o acp-stream.o acp-trace.o acp-common.o
-snd-sof-amd-acp-$(CONFIG_SND_SOC_SOF_ACP_PROBES) = acp-probes.o
+snd-sof-amd-acp-$(CONFIG_SND_SOC_SOF_ACP_PROBES) += acp-probes.o
 snd-sof-amd-renoir-y := pci-rn.o renoir.o
 snd-sof-amd-rembrandt-y := pci-rmb.o rembrandt.o
 snd-sof-amd-vangogh-y := pci-vangogh.o vangogh.o
-- 
2.43.0