m68k: kernel: Add and use "vectors.h"

When building with W=1:

arch/m68k/kernel/vectors.c:52:13: warning: no previous prototype for ‘base_trap_init’ [-Wmissing-prototypes]
52 | void __init base_trap_init(void)
| ^~~~~~~~~~~~~~

Fix this by introducing a new header file "vectors.h" for holding the
prototypes of functions implemented in arch/m68k/kernel/vectors.c.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/bd0a2f65bc1681dc45e2b24951bd89f9ddbe2eef.1694613528.git.geert@linux-m68k.org

m68k: kernel: Include <linux/cpu.h> for trap_init()

When building with W=1:

arch/m68k/kernel/vectors.c:74:13: warning: no previous prototype for ‘trap_init’ [-Wmissing-prototypes]
74 | void __init trap_init (void)
| ^~~~~~~~~

Fix this by including <linux/cpu.h>.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/42e7055fab50deda1f7cd648982e90b7ab28fdc3.1694613528.git.geert@linux-m68k.org

Disintegrate asm/system.h for M68K

Disintegrate asm/system.h for M68K.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@uclinux.org>
cc: linux-m68k@lists.linux-m68k.org

m68k: move hardware vector setting from traps.c to its own file

Most of the trap.c code is general to all m68k arch members. But the code
it currently contains to set the hardware vector table is quite specific to
the 680x0 family. They can have the vector table at any address unlike
other family members (which either support only a single fixed address,
or a limited range of addresses). So lets move that code out to a new file,
vectors.c. This will make sharing the rest of the trap.c code easier and
cleaner.

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