ALSA: docs: Correct the kernel object suffix of target

The correct suffix is 'y' for the kernel code and
'objs' for the user space. Update documentation.

Signed-off-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

Documentation/sound/kernel-api/writing-an-alsa-driver.rst

···
 
    Suppose you have a file xyz.c. Add the following two lines::
 
-     snd-xyz-objs := xyz.o
+     snd-xyz-y := xyz.o
      obj-$(CONFIG_SND_XYZ) += snd-xyz.o
 
 2. Create the Kconfig entry
···
 
 2. Under the directory ``sound/pci/xyz``, create a Makefile::
 
-         snd-xyz-objs := xyz.o abc.o def.o
+         snd-xyz-y := xyz.o abc.o def.o
          obj-$(CONFIG_SND_XYZ) += snd-xyz.o
 
 3. Create the Kconfig entry