m68k: sun3/3x: Include <asm/config.h> for config_sun3*()

When building with W=1:

arch/m68k/sun3/config.c:123:13: warning: no previous prototype for ‘config_sun3’ [-Wmissing-prototypes]
126 | void __init config_sun3(void)
| ^~~~~~~~~~~
arch/m68k/sun3x/config.c:42:13: warning: no previous prototype for ‘config_sun3x’ [-Wmissing-prototypes]
42 | void __init config_sun3x(void)
| ^~~~~~~~~~~~

Fix this by including <asm/config.h>

Fixes: 91d7b75a5888c182 ("m68k: Add asm/config.h")
Signed-off-by: Geert Uytterhoeven <[e-mail]>
Acked-by: Arnd Bergmann <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/m68k/sun3/config.c

···
 #include <asm/irq.h>
 #include <asm/sections.h>
 #include <asm/sun3ints.h>
+#include <asm/config.h>
 
 char sun3_reserved_pmeg[SUN3_PMEGS_NUM];
 

arch/m68k/sun3x/config.c

···
 #include <asm/sun3ints.h>
 #include <asm/setup.h>
 #include <asm/oplib.h>
+#include <asm/config.h>
 
 #include "time.h"