Avoid array overrun. We can now mount the /sdcard partition on our boot sdcards

Orig-Change-Id: I6e9db8c55db49b4aa61dd40cd59495f55e5b3368
Signed-off-by: Bruce Beare <brucex.j.beare@intel.com>
diff --git a/DirectVolume.cpp b/DirectVolume.cpp
index 0ac1a0c..a570a73 100644
--- a/DirectVolume.cpp
+++ b/DirectVolume.cpp
@@ -202,9 +202,13 @@
 #ifdef PARTITION_DEBUG
     SLOGD("Dv:partAdd: part_num = %d, minor = %d\n", part_num, minor);
 #endif
-    mPartMinors[part_num -1] = minor;
-
+    if (part_num >= MAX_PARTITIONS) {
+        SLOGE("Dv:partAdd: ignoring part_num = %d (max: %d)\n", part_num, MAX_PARTITIONS-1);
+    } else {
+        mPartMinors[part_num -1] = minor;
+    }
     mPendingPartMap &= ~(1 << part_num);
+
     if (!mPendingPartMap) {
 #ifdef PARTITION_DEBUG
         SLOGD("Dv:partAdd: Got all partitions - ready to rock!");