libxml-libxml-perl: update from 2.0116 to 2.0121

update to 2.0121 and clean unused logic:

  - do_configure_prepend() {
  -        rm -rf ${S}/.pc/*
  - }

Signed-off-by: Wenzong Fan <wenzong.fan@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>