Exynos: fix gralloc build

Change-Id: Iae8c7cf947aacb6ec5c952a10a14b9d41c397ed2
diff --git a/exynos4/hal/libgralloc_ump/framebuffer_device.cpp b/exynos4/hal/libgralloc_ump/framebuffer_device.cpp
index cfdedba..b141878 100644
--- a/exynos4/hal/libgralloc_ump/framebuffer_device.cpp
+++ b/exynos4/hal/libgralloc_ump/framebuffer_device.cpp
@@ -322,7 +322,7 @@
     module->ydpi = ydpi;
     module->fps = fps;
 
-    char value[32];
+    char value[PROPERTY_VALUE_MAX];
     property_get("debug.gralloc.vsync", value, "1");
     module->enableVSync = atoi(value);
     /*