[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>