The vfree() function performs also input parameter validation.
Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/8060f2e9-5070-3c10-d55c-dc058e4ca20d@users.sourceforge.net
Link: http://patchwork.freedesktop.org/patch/msgid/f1a0fd83-4320-f3db-e1bb-3b9832a4429f@users.sourceforge.net