blacklist.bbclass: fix for multilib

blacklist.bbclass: fix for multilib

* Fixed:
  The netmap has been blacklisted in
  meta-networking/recipes-kernel/netmap/netmap_git.bb, but lib32-netmap still can
  be built (suppose it doesn't depend on another broken recipe netmap-modules, it
  is a little complicated, will talk below):
  $ bitbake lib32-netmap

  This is because of the old code masks on bb.event.ConfigParsed which can only
  handle global blacklist, netmap sets blacklist in the recipe, so it can't be
  handled, and lib32-netmap can be built. which was incorrect:
  blacklist_multilib_eventhandler[eventmask] = "bb.event.ConfigParsed"

  Move multilib code into multilib.bbclass can fix the problem easily:
  $ bitbake lib32-netmap
    ERROR: Nothing PROVIDES 'lib32-netmap'
    ERROR: lib32-netmap was skipped: Recipe is blacklisted: BROKEN: <foo>

* Not fixed
  Another problem is netmap-modules has also been blacklisted in the recipe, and
  the recipe inherits module.bbclass, so multilib.bbclass doesn't handle it as the
  code shows:
    # There should only be one kernel in multilib configs
    # We also skip multilib setup for module packages.
    provides = (e.data.getVar("PROVIDES") or "").split()
    if "virtual/kernel" in provides or bb.data.inherits_class('module-base', e.data):
        raise bb.parse.SkipPackage("We shouldn't have multilib variants for the kernel")

  And netmap-modules provides lib32-netmap-modules which is handled in
  multilib_global.bbclass, so bitbake lib32-netmap-modules can't show
  the blacklist message:
  $ bitbake netmap-modules
  ERROR: Nothing PROVIDES 'netmap-modules'
  ERROR: netmap-modules was skipped: Recipe is blacklisted: BROKEN: <foo>
  ERROR: netmap-modules was skipped: We shouldn't have multilib variants for the kernel

  $ bitbake lib32-netmap-modules
  ERROR: Nothing PROVIDES 'lib32-netmap-modules'. Close matches:
    netmap-modules
    netmap-modules
    lib32-fbset-modes

  Note the different messages between netmap-modules and lib32-netmap-modules.
  This is because multilib.bbclass doesn't handle the "module" recipe so
  there is no PN called lib32-netmap-modules, therefore blacklist.bbclass can't
  handle it.

  Note, there are two "netmap-modules" which needs to be fixed later.

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>