MT#61848 Add missing mdadm dependencies for ngcp-addons-*

This package is needed to support software RAID. We have it installed
on NGCP by the installer, but no other package depends on it, so it
could end up being removed, during an upgrade or due to user error.

Change-Id: I8a46095bbee40c09b5edf5bbdd62363011b33ee0

debian/control

@@ -169,6 +169,7 @@ Depends:
  lsb-release,
  lsof,
  man-db,
+ mdadm,
  moreutils,
  nano,
  ngcp-inventory-pro,
@@ -245,6 +246,7 @@ Depends:
  lsb-release,
  lsof,
  man-db,
+ mdadm,
  moreutils,
  nano,
  ngcp-deployment-scripts,