Remove the checking of yaboot-xcat to support removing yaboot-xcat rpm.

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@14517 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server/lib/xcat/plugins/mknb.pm

@@ -171,9 +171,6 @@ sub process_request {
       }
    } elsif ($arch =~ /ppc/) {
       mkpath("$tftpdir/etc");
-      if (! -r "$tftpdir/yaboot") {
-          $callback->({error=>["Unable to locate yaboot to boot ppc clients, install yaboot-xcat"],errorcode=>[1]});
-      }
    }
    my $dopxe=0;
    foreach (keys %{$normnets}) {