package/rpi-userland: add patch to remove faulty assert()

While porting wayland/weston to run on the RPi, I always tripped on
this assert.

Thinking there was an issue with weston, I poked the weston guys on
IRC about the issue. 'daniels' on irc.freenode.net/#wayland suggested
removing the assert altogether, as that's what they had pushed
upstream in their wayland pull-request:
    https://github.com/raspberrypi/userland/pull/92



Turns out they forgot to include this in their pull-request, but that
they were using a patched rpi-userland without that assert.

And indeed, without that assert, weston runs on the RPi. :-)

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>