m68knommu: fix broken boot logo inclusion

Compiling for the m68knommu/68328 Palm/Pilot target you get:

  AS      arch/m68k/platform/68328/head-pilot.o
arch/m68k/platform/68328/head-pilot.S:37:23: fatal error: bootlogo.rh: No such file or directory

The build for this target used to do a conversion on a C coded boot logo
and include this in the head assembler code. This got broken by changes to
the local Makefile.

Clean all this up by just including the C coded boot logo struct in the
C code. With the appropriate alignment attribute there is no difference
to the way it can be used.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>