[ALSA] Fix build error without CONFIG_HAS_DMA

The recent change of include/asm-generic/dma-mapping-broken.h breaks
the build without CONFIG_HAS_DMA.  This patch is an ad hoc fix.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/core/Makefile b/sound/core/Makefile
index 5a01c76..05f5cdc 100644
--- a/sound/core/Makefile
+++ b/sound/core/Makefile
@@ -14,7 +14,8 @@
 snd-pcm-objs := pcm.o pcm_native.o pcm_lib.o pcm_timer.o pcm_misc.o \
 		pcm_memory.o
 
-snd-page-alloc-objs := memalloc.o sgbuf.o
+snd-page-alloc-y := memalloc.o
+snd-page-alloc-$(CONFIG_HAS_DMA) += sgbuf.o
 
 snd-rawmidi-objs  := rawmidi.o
 snd-timer-objs    := timer.o