Platform/RaspberryPi: Remove RPi GraphicsConsoleDxe

Remove the PI specific GraphicsConsoleDxe driver, since RPi3/RPi4
switched to using the common driver in MdeModulePkg.

Signed-off-by: Samer El-Haj-Mahmoud <samer@elhajmahmoud.com>
Reviewed-by: Andrei Warkentin <andrey.warkentin@gmail.com>