Remove the MN10300 arch as the hardware is defunct.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Masahiro Yamada <yamada.masahiro@socionext.com>
cc: linux-am33-list@redhat.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Create generic kernel debugger hooks in the MN10300 arch and make gdbstub use
them.  This is a preparation for KGDB support.

Signed-off-by: David Howells <dhowells@redhat.com>

Create general kernel debugger cache flushing for MN10300 and get rid of the
old stuff that gdbstub was using.

Signed-off-by: David Howells <dhowells@redhat.com>

Introduce a general config option for kernel debugger hooks so that both
gdbstub and kgdb can use it and add a header file for both debuggers to use.

Signed-off-by: David Howells <dhowells@redhat.com>