Revert "QtPrintSupport: Remove remaining LPR specific code"

Revert "QtPrintSupport: Remove remaining LPR specific code"

This doesn't compile with a typical cross-compilation setup, which
generally won't include cups headers.  The commit should have been
rejected, but wasn't, due to a bug in the Qt Project CI.

Since it now causes all other modules depending on qtbase to fail their
CI, it must be reverted to minimize disruption while the commit can be
amended and/or the test toolchain updated to include cups headers.

This reverts commit 80f7a388906f94f58bf765a32b9abbb16f967db2.

Change-Id: I315ae275b37de358a74af28ab7bd691c9849acba
Reviewed-by: Sergio Ahumada <sergio.ahumada@nokia.com>
Reviewed-by: Toby Tomkins <toby.tomkins@nokia.com>