package/{wlroots,cage}: change mesa3d dependency to virtual libegl/libgles

package/{wlroots,cage}: change mesa3d dependency to virtual libegl/libgles

Since commits:
https://github.com/swaywm/wlroots/commit/c2288a7b88240e4377bfc1c67b44efb58f704a42
https://github.com/swaywm/wlroots/commit/e18599b05e0f0cbeba11adbd489e801285470eab

Mesa dependency is no longer required. Wlroots is able to run on
drivers that provide EGL and GLES2.0 support, and with specific EGL
wayland extensions.  (thus the BR2_PACKAGE_HAS_LIBEGL_WAYLAND
dependency)

This was verified on NXP's i.MX8MMini using imx-gpu-viv driver.

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Gilles Talis <gilles.talis@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>