Use "dp" instead of "sp"

Change-Id: I772d117d88eb7361d8695c4d97c051f0c7397df8
diff --git a/java/res/layout/key_preview.xml b/java/res/layout/key_preview.xml
index b620d07..6ed892e 100644
--- a/java/res/layout/key_preview.xml
+++ b/java/res/layout/key_preview.xml
@@ -20,8 +20,8 @@
 
 <TextView xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="wrap_content"
-    android:layout_height="80sp"
-    android:textSize="40sp"
-    android:minWidth="32dip"
+    android:layout_height="80dp"
+    android:textSize="40dp"
+    android:minWidth="32dp"
     android:gravity="center"
     />