Add cpio.

Sony asked for this to be included for some reason. Fine by me.

Bug: 18464157
Change-Id: I497d6d8fe8a912b5c503663cfb12d9de7803343b
diff --git a/Android.mk b/Android.mk
index 750d704..75b2b25 100644
--- a/Android.mk
+++ b/Android.mk
@@ -132,6 +132,7 @@
     toys/posix/cmp.c \
     toys/posix/comm.c \
     toys/posix/cp.c \
+    toys/posix/cpio.c \
     toys/posix/cut.c \
     toys/posix/date.c \
     toys/posix/df.c \
@@ -212,6 +213,7 @@
     comm \
     cmp \
     cp \
+    cpio \
     cut \
     date \
     dirname \