surfaceflinger: fix -Wunused-parameter warning

warning: unused parameter 'mustRecompose' [-Wunused-parameter]

Change-Id: I6b8c671189639d851bfa5548742de988d6fa2687
(cherry picked from d2e514f71709e6af3dbc754e59686129737f2300)
diff --git a/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp b/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp
index 086ccf8..b767983 100644
--- a/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp
+++ b/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp
@@ -68,7 +68,7 @@
     mConsumer->setDefaultMaxBufferCount(NUM_FRAMEBUFFER_SURFACE_BUFFERS);
 }
 
-status_t FramebufferSurface::beginFrame(bool mustRecompose) {
+status_t FramebufferSurface::beginFrame(bool /*mustRecompose*/) {
     return NO_ERROR;
 }