MIPS: SEAD3: Drop use of cobalt fbdev driver

MIPS: SEAD3: Drop use of cobalt fbdev driver

The 2 line * 16 character LCD display on the SEAD3 board has no real use
as a framebuffer device. It's far too small to produce any meaningful
output if used as the kernel console, SEAD3 is a development board that
will essentially always have a far more useful UART connection & the
code in sead3-display.c will overwrite whatever's on the display every
second anyway. Remove this unused code.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14059/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>