raspberrypi.conf: Weakly assign PREFERRED_PROVIDER_virtual/egl
raspberrypi.conf: Weakly assign PREFERRED_PROVIDER_virtual/egl

Use vc-graphics-hardfp by default as virtual/egl and let the user
overwrite this.

Signed-off-by: Andrei Gherzan <8dc7c09356db0b1762fb140617d7375c0a5a4131@gherzan.ro>

sarnold/meta-alt-desktop-extras,sarnold/meta-alt-desktop-extras,sarnold/meta-alt-desktop-extras