include, target: Change naming convention for vb runtime detection.

Change naming convention VB runtime detection.
VB_L represents the VB for L upgrades, VB_M represents VB1.0 for
M upgrades.

Change-Id: I6f9d7010a427db3236231ca5d594ad30c4cc8d2f
diff --git a/include/target.h b/include/target.h
index a1f9f49..2f1acfe 100644
--- a/include/target.h
+++ b/include/target.h
@@ -35,8 +35,8 @@
 /* Enum for target VB version detection */
 enum
 {
-	VB_V1 = 1,
-	VB_V2 = 2,
+	VB_L = 1,
+	VB_M = 2,
 };
 
 /* Target helper functions exposed to USB driver */