compcache hook should add spare zram devices

These days zram leaves staging and in many cases can be seen as ramdisk replacement.
Currently compcache hook loads driver with single device instance, blocking any additional usage of zram driver.

I suggest to add 16 /dev/zramX devices (same amount as with /dev/ramX).
That won't affect current zram utilization by compcache hook but will allow convenient usage of zram for other purposes.

Below is trivial change is required to achieve above:
--- a/hook/compcache
+++ b/hook/compcache
@@ -138,7 +138,7 @@

 if [ "$name" = zram ]; then
   cat >>"$DESTDIR"/scripts/init-top/compcache <<EOF
-modprobe -q --ignore-install zram
+modprobe -q --ignore-install zram num_devices=16
 EOF
 elif [ "$name" = ramzswap ]; then
   cat >>"$DESTDIR"/scripts/init-top/compcache <<EOF