Configure: add -no-wmf-backend option

This option is required to build qtmultimedia without
Windows Media Foundation backend. In this case,
a full DirectShow backend will be build instead.

Change-Id: Ib29ba81ca6cbb00b609cc97fab7da29e61d31d6d
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>