media/mtp: Add missing LOCAL_C_INCLUDES

One of the source files here is including <cutils/tztime.h> which
itself includes <bionic_time.h>, a private C library header used
to define the strftime_tz() extension (which used to be declared
in <time.h> but was moved there instead).

Add a missing C include path to let our code compile as usual.

Change-Id: I6aac2f1d3d15ad182679c81ff3f4febff74eb671

media/mtp/Android.mk

@@ -39,6 +39,9 @@ LOCAL_MODULE:= libmtp
 
 LOCAL_CFLAGS := -DMTP_DEVICE -DMTP_HOST
 
+# Needed for <bionic_time.h>
+LOCAL_C_INCLUDES := bionic/libc/private
+
 LOCAL_SHARED_LIBRARIES := libutils libcutils libusbhost libbinder
 
 include $(BUILD_SHARED_LIBRARY)