arm: move edb93xx to generic board architecture

Use CONFIG_SYS_GENERIC_BOARD in EDB93XX board family
diff --git a/include/configs/edb93xx.h b/include/configs/edb93xx.h
index efe2a9d..e3e32aa 100644
--- a/include/configs/edb93xx.h
+++ b/include/configs/edb93xx.h
@@ -25,6 +25,8 @@
 #error "no board defined"
 #endif
 
+#define CONFIG_SYS_GENERIC_BOARD
+
 /* Initial environment and monitor configuration options. */
 #define CONFIG_BOOTDELAY		2
 #define CONFIG_CMDLINE_TAG		1