EGL: make max cache key size BoardConfig-able

This change makes the maximum EGL blob cache key size configurable via a
BoardConfig.

Change-Id: Ic669cd25fc743662bd4f13aab62354fc3d54560c
diff --git a/opengl/libs/EGL/egl_cache.cpp b/opengl/libs/EGL/egl_cache.cpp
index ed2bef3..72655df 100644
--- a/opengl/libs/EGL/egl_cache.cpp
+++ b/opengl/libs/EGL/egl_cache.cpp
@@ -29,12 +29,16 @@
 #define MAX_EGL_CACHE_ENTRY_SIZE (16 * 1024);
 #endif
 
+#ifndef MAX_EGL_CACHE_KEY_SIZE
+#define MAX_EGL_CACHE_KEY_SIZE (1024);
+#endif
+
 #ifndef MAX_EGL_CACHE_SIZE
 #define MAX_EGL_CACHE_SIZE (64 * 1024);
 #endif
 
 // Cache size limits.
-static const size_t maxKeySize = 1024;
+static const size_t maxKeySize = MAX_EGL_CACHE_KEY_SIZE;
 static const size_t maxValueSize = MAX_EGL_CACHE_ENTRY_SIZE;
 static const size_t maxTotalSize = MAX_EGL_CACHE_SIZE;