staging/goldfish/goldfish_audio: Fix annotations

dmam_alloc_coherent does not return a __iomem pointer.
here is its prototype:

void * dmam_alloc_coherent(struct device *dev, size_t size,
			   dma_addr_t *dma_handle, gfp_t gfp)

This fixes these sparse warnings:

drivers/staging/goldfish/goldfish_audio.c:134:43: warning: incorrect
type in argument 2 (different address spaces)
drivers/staging/goldfish/goldfish_audio.c:134:43:    expected void const
*from
drivers/staging/goldfish/goldfish_audio.c:134:43:    got char [noderef]
<asn:2>*read_buffer
drivers/staging/goldfish/goldfish_audio.c:167:36: warning: incorrect
type in argument 1 (different address spaces)
drivers/staging/goldfish/goldfish_audio.c:167:36:    expected void *to
drivers/staging/goldfish/goldfish_audio.c:167:36:    got char [noderef]
<asn:2>*[assigned] kbuf
drivers/staging/goldfish/goldfish_audio.c:296:27: warning: incorrect
type in assignment (different address spaces)
drivers/staging/goldfish/goldfish_audio.c:296:27:    expected char
[noderef] <asn:2>*buffer_virt
drivers/staging/goldfish/goldfish_audio.c:296:27:    got void *

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/goldfish/goldfish_audio.c

@@ -40,12 +40,12 @@ struct goldfish_audio {
 	spinlock_t lock;
 	wait_queue_head_t wait;
 
-	char __iomem *buffer_virt;      /* combined buffer virtual address */
+	char *buffer_virt;		/* combined buffer virtual address */
 	unsigned long buffer_phys;      /* combined buffer physical address */
 
-	char __iomem *write_buffer1;    /* write buffer 1 virtual address */
-	char __iomem *write_buffer2;    /* write buffer 2 virtual address */
-	char __iomem *read_buffer;      /* read buffer virtual address */
+	char *write_buffer1;		/* write buffer 1 virtual address */
+	char *write_buffer2;		/* write buffer 2 virtual address */
+	char *read_buffer;		/* read buffer virtual address */
 	int buffer_status;
 	int read_supported;         /* true if we have audio input support */
 };
@@ -147,7 +147,7 @@ static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
 	struct goldfish_audio *data = fp->private_data;
 	unsigned long irq_flags;
 	ssize_t result = 0;
-	char __iomem *kbuf;
+	char *kbuf;
 
 	while (count > 0) {
 		ssize_t copy = count;