Bug#980971: ghostscript lacks opvp support, breaks some printer backends

[Chris Bainbridge <chris.bainbridge@gmail.com>]

Package: ghostscript

Version: 9.53.3~dfsg-6

As reported at https://bugzilla.redhat.com/show_bug.cgi?id=1899885 ghostscript upstream temporarily disabled opvp support, breaking Canon CAPT/UFR printer driver support in cups. This change has since been reverted upstream. I can confirm that the patch at https://git.ghostscript.com/?p=ghostpdl.git;a=patch;h=c6ce09aa5c9e does restore Canon printer functionality in bullseye.