lubbock: Fix no partition type specified, use DOS as default

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

include/configs/lubbock.h

@@ -42,6 +42,7 @@
 #endif
 #define CONFIG_MMC		1
 #define BOARD_LATE_INIT		1
+#define CONFIG_DOS_PARTITION
 
 #undef CONFIG_USE_IRQ			/* we don't need IRQ/FIQ stuff */