MIPS: SEAD3: Use img-ascii-lcd driver

Probe the img-ascii-lcd driver using device tree in order to display a
message on the SEAD3 board's LCD display, and remove the platform code
that was formerly performing this function. This removes more platform
code and moves SEAD3 further towards being entirely DT-based.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14063/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>