devel/plasma: Fix BUILD_DEPENDS after 26194763

* The recently updated devel/py-capstone, which is used as RUN_DEPENDS
  pulls in devel/capstone which leads to conflicting dependendies with
  devel/capstone4 which is installed prior during the build phase.

  Fix the issue by switching the BUILD_DEPENDS to devel/capstone.

* Bump PORTREVISION due changed package contents as the shared libs are
  created from the more recent devel/capstone.

Reported by:	pkg-fallout