includes: Fix typo in mmdeviceapi.idl.

include/mmdeviceapi.idl

diff --git a/include/mmdeviceapi.idl b/include/mmdeviceapi.idl
index e452e89..d1fb6ae 100644
--- a/include/mmdeviceapi.idl
+++ b/include/mmdeviceapi.idl
@@ -174,7 +174,7 @@
     nonextensible,
     pointer_default(unique)
 ]
-interface IMMEndPoint : IUnknown
+interface IMMEndpoint : IUnknown
 {
     [id(1)] HRESULT GetDataFlow(
         [out] EDataFlow *pDataFlow