dbb4457d started using drmDevicesEqual(), which was introduced in libdrm 2.4.81
We could either copy the function locally, or bump the required version. Since the function is non-trivial and 2.4.81 is old enough already, I suggesting the latter.
Fixes: dbb4457d ("egl: add EGL_EXT_device_drm support")
Cc: @evelikov