gvt-fixes-2018-04-19

- cmd parser error path mem leak fix (Colin)
- fix dp aux header validation (Changbin)
- sanity check on pfn after vfio pin page (Changbin)
- fix msi eventfd put (Xiong)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180419073948.4mojv7xaxxvfuyud@zhen-hp.sh.intel.com