ASoC: sprd: Use *-y instead of *-objs in Makefile

*-objs suffix is reserved rather for (user-space) host programs while
usually *-y suffix is used for kernel drivers (although *-objs works
for that purpose for now).

Let's correct the old usages of *-objs in Makefiles.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240507155540.24815-27-tiwai@suse.deSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sprd/Makefile

 # SPDX-License-Identifier: GPL-2.0
 # Spreadtrum Audio Support
 
-snd-soc-sprd-platform-objs := sprd-pcm-dma.o sprd-pcm-compress.o
+snd-soc-sprd-platform-y := sprd-pcm-dma.o sprd-pcm-compress.o
 
 obj-$(CONFIG_SND_SOC_SPRD) += snd-soc-sprd-platform.o