include: replace unifdef-y with header-y

unifdef-y and header-y has same semantic.
So there is no need to have both.

Drop the unifdef-y variant and sort all lines again

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

include/sound/Kbuild

@@ -1,9 +1,8 @@
+header-y += asequencer.h
+header-y += asound.h
 header-y += asound_fm.h
+header-y += emu10k1.h
 header-y += hdsp.h
 header-y += hdspm.h
+header-y += sb16_csp.h
 header-y += sfnt_info.h
-
-unifdef-y += asequencer.h
-unifdef-y += asound.h
-unifdef-y += emu10k1.h
-unifdef-y += sb16_csp.h