ALSA: core: memalloc: add page alignment for iram

Since mmap for userspace is based on page alignment, add page alignment
for iram alloc from pool, otherwise, some good data located in the same
page of dmab->area maybe touched wrongly by userspace like pulseaudio.
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1608221747-3474-1-git-send-email-yibin.gong@nxp.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/memalloc.c

@@ -77,7 +77,8 @@ static void snd_malloc_dev_iram(struct snd_dma_buffer *dmab, size_t size)
 	/* Assign the pool into private_data field */
 	dmab->private_data = pool;
 
-	dmab->area = gen_pool_dma_alloc(pool, size, &dmab->addr);
+	dmab->area = gen_pool_dma_alloc_align(pool, size, &dmab->addr,
+					PAGE_SIZE);
 }
 
 /**