m68knommu: fix missing LCD splash screen data initializer

The kernel test robot reports that the "screen_bits" splash screen data
is missing for the dragen platform:

    arch/m68k/68000/dragen2.c:73:16: error: 'screen_bits' undeclared (first use in this function)
      73 |  LSSA = (long) screen_bits;
         |                ^~~~~~~~~~~
    arch/m68k/68000/dragen2.c:73:16: note: each undeclared identifier is reported only once for each function it appears in

Digging around a bit I found the screen_bits data structure was originally
in a screen.h file that was generated from a screen.xbm file. That was
removed in commit 0c0e6db ("m68k: drop unused parts of 68VZ328
Makefile").

Other splash screen initializers for 68000 targets are kept here as the
C data structures so lets do the same for this one. Add the missing
screen.h file and include it in the dragen specific startup code.

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Greg Ungerer <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>

arch/m68k/68000/dragen2.c

@@ -11,6 +11,7 @@
 #include <linux/init.h>
 #include <asm/machdep.h>
 #include <asm/MC68VZ328.h>
+#include "screen.h"
 
 /***************************************************************************/
 /*                        Init Drangon Engine hardware                     */