autotools: add -I/src/egl to tizonia

autotools: add -I/src/egl to tizonia

This fixes the following build breakage:

make[5]: Entering directory
'/mnt/sdc1/Gits/mesa/src/gallium/state_trackers/omx/tizonia'
   CC       h264dprc.lo
In file included from h264dprc.c:45:0:
../../../../../src/egl/drivers/dri2/egl_dri2.h:47:10: fatal error:
wayland/wayland-egl/wayland-egl-backend.h: No such file or directory
  #include "wayland/wayland-egl/wayland-egl-backend.h"
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.

meson got the same fix in 7598dedfde49391564cdb3d355e7bd98e1880782.

Signed-off-by: Dylan Baker <dylan.c.baker@intel.com>
Acked-by: Emil Velikov <emil.velikov@collabora.com>