qt5base: Patch Qt config to detect sunxi-mali

Currently Qt 5.5 only detects and build the eglfs_mali device
integration if the commercial Mali driver package from ARM is used.
This patch makes sure the Qt configure script also test for the
sunxi-mali driver package. It also removes the dependency of
the proprietary fbdev_window.h.

This issue is set to be fixed in upcoming Qt 5.6:
https://codereview.qt-project.org/#/c/125837/



[Thomas: renumber patch from 0010 to 0009.]

Signed-off-by: Daniel Nyström <daniel.nystrom@timeterminal.se>
Tested-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
[Thomas: build tested before the patch, verified that indeed the
eglfs-mali plugin doesn't get built, and that after the patch it gets
built as expected.]