japanese/fcitx5-cskk: Depend on ECM unconditionally

The top-level CMakeLists.txt calls find_package(ECM 1.0.0 REQUIRED)
unconditionally, but the port only declared the dependency under the QT5
option, so configure fails with WITHOUT_QT5. Move it out of the option
and make it build-only. ECM is listed in _USE_KDE_LATEST, so USES=kde:5
can be dropped along with it, as done in 95f9a6808973 for the other
fcitx5 ports.

While here, fix the indentation of PORTREVISION.

PR: 297623
Approved by: syobon@syobon.net (maintainer)
Approved by: osa (mentor)