xserver-xorg-video-nouveau 1:1.0.17-3 FTBFS on armhf

[Benjamin Drung]

xserver-xorg-video-nouveau 1:1.0.17-3 fails to build on armhf:

```
libtool: compile: gcc -DHAVE_CONFIG_H -I. -I../../src -I.. -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64 -Wdate-time -D_FORTIFY_SOURCE=3 -I/usr/include/xorg -fvisibility=hidden -I/usr/include/pixman-1 -I/usr/include/X11/dri -I/usr/include/libdrm -I/usr/include/libdrm -I/usr/include/libdrm/nouveau -I/usr/include/libdrm -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -fno-stack-clash-protection -fdebug-prefix-map=/<<PKGBUILDDIR>>=/usr/src/xserver-xorg-video-nouveau-1:1.0.17-3 -Wall -I/usr/include/xorg -fvisibility=hidden -I/usr/include/pixman-1 -I/usr/include/X11/dri -I/usr/include/libdrm -c ../../src/nv_shadow.c -fPIC -DPIC -o .libs/nv_shadow.o
../../src/nv_driver.c: In function ‘NVScreenInit’:
../../src/nv_driver.c:1451:23: error: implicit declaration of function ‘wfbScreenInit’; did you mean ‘fbScreenInit’? [-Werror=implicit-function-declaration]
 1451 | ret = wfbScreenInit(pScreen, FBStart, pScrn->virtualX,
      | ^~~~~~~~~~~~~
      | fbScreenInit
```

This failure is fixed upstream in xorg-server via https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1114

[Timo Aaltonen (tjaalton)]

the upstream backport request has more context

https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1222

and it's not clear that this wouldn't be a bug in nouveau instead