x11-toolkits/libdecor: temporarily drop subpackages

https://github.com/freebsd/poudriere/issues/1113
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=276845

Requested by: makc (kde), bdrewery (pkgmgr)
Suggested by: pizzamig (portmgr)

This reverts commit bd94cb1ba7c16218a0b35638aa319b5f1d73e1e5.
This reverts commit bb176de034ea795cfb1830588f5ac73a42ec0b70.
This reverts commit 1a1e43198c5a1b80cab83b342793db74c23dad78.