Fix CryptoInfo.toString

It's using the key length when it should use the iv length.

Bug: 154120292
Test: Manually.
Change-Id: I98d71b974688acbeef0c7112298c5edf37d47ef7
diff --git a/media/java/android/media/MediaCodec.java b/media/java/android/media/MediaCodec.java
index 62d76c0..0780c68 100644
--- a/media/java/android/media/MediaCodec.java
+++ b/media/java/android/media/MediaCodec.java
@@ -2762,7 +2762,7 @@
                 builder.append(hexdigits.charAt(key[i] & 0x0f));
             }
             builder.append("], iv [");
-            for (int i = 0; i < key.length; i++) {
+            for (int i = 0; i < iv.length; i++) {
                 builder.append(hexdigits.charAt((iv[i] & 0xf0) >> 4));
                 builder.append(hexdigits.charAt(iv[i] & 0x0f));
             }