ASoC: mxs: 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/20240507155540.24815-19-tiwai@suse.deSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/mxs/Makefile

 # SPDX-License-Identifier: GPL-2.0
 # MXS Platform Support
-snd-soc-mxs-objs := mxs-saif.o
-snd-soc-mxs-pcm-objs := mxs-pcm.o
+snd-soc-mxs-y := mxs-saif.o
+snd-soc-mxs-pcm-y := mxs-pcm.o
 
 obj-$(CONFIG_SND_MXS_SOC) += snd-soc-mxs.o snd-soc-mxs-pcm.o
 
 # i.MX Machine Support
-snd-soc-mxs-sgtl5000-objs := mxs-sgtl5000.o
+snd-soc-mxs-sgtl5000-y := mxs-sgtl5000.o
 
 obj-$(CONFIG_SND_SOC_MXS_SGTL5000) += snd-soc-mxs-sgtl5000.o