Bug#1109780: gst-plugins-bad1.0-contrib: Enable riscv64 build

[Bastian Germann <bage@debian.org>]

Package: gst-plugins-bad1.0-contrib
Severity: wishlist
X-Debbugs-Cc: debian-riscv@lists.debian.org
User: debian-riscv@lists.debian.org
Usertags: riscv64

Please enable riscv64 builds. Instead of adding it to the extensive
architectures list consider switching to Arch: any and removing the arch
qualifiers from Build-Depends. The package does not build automatically
on the buildd network, so it does not make a lot of sense to qualify the
architectures.