aaudio: fix mmap result checking

Was checking for nullptr not MAP_FAILED

Bug: 33398120
Test: see mmap() docs
Change-Id: I02d178cb0188f8b0d6cd009699dccc7c97952e4b
Signed-off-by: Phil Burk <philburk@google.com>
diff --git a/services/oboeservice/SharedRingBuffer.cpp b/services/oboeservice/SharedRingBuffer.cpp
index efcc9d6..03c160d 100644
--- a/services/oboeservice/SharedRingBuffer.cpp
+++ b/services/oboeservice/SharedRingBuffer.cpp
@@ -18,6 +18,8 @@
 //#define LOG_NDEBUG 0
 #include <utils/Log.h>
 
+#include <sys/mman.h>
+
 #include "binding/RingBufferParcelable.h"
 #include "binding/AudioEndpointParcelable.h"