audio: MMAP NOIRQ mode shareable file descriptor

Derive a shareable file descriptor for the DMA buffer
used for MMAP NOIRQ

Change-Id: Ibdd633fad35ed397f6de746e5755a02522e39777
diff --git a/hal/msm8960/platform.c b/hal/msm8960/platform.c
index f2201db..43aeaed 100644
--- a/hal/msm8960/platform.c
+++ b/hal/msm8960/platform.c
@@ -1368,3 +1368,9 @@
 {
     return 0;
 }
+
+int platform_get_mmap_data_fd(void *platform, int fe_dev, int dir, int *fd,
+                              uint32_t *size)
+{
+    return -ENOSYS;
+}