Move cat(1) to toybox.

Test: builds
Change-Id: I9a367c3204891518994bfe889072dd1cf9aed490
diff --git a/ui/build/paths/config.go b/ui/build/paths/config.go
index f3406e5..6cab573 100644
--- a/ui/build/paths/config.go
+++ b/ui/build/paths/config.go
@@ -79,7 +79,6 @@
 	"bash":      Allowed,
 	"bc":        Allowed,
 	"bzip2":     Allowed,
-	"cat":       Allowed,
 	"chmod":     Allowed,
 	"cmp":       Allowed,
 	"comm":      Allowed,
@@ -174,6 +173,7 @@
 	"pkg-config": Forbidden,
 
 	// On linux we'll use the toybox version of these instead
+	"cat":    Toybox,
 	"id":     Toybox,
 	"true":   Toybox,
 	"uname":  Toybox,