Add sparc_leon enum, M_LEON|M_LEON3_SOC machine. Add compilation of
leon.c in mm and kernel
if CONFIG_SPARC_LEON is defined. Add sparc_leon dependent
initialization to switch statements + head.S.

Signed-off-by: Konrad Eisele <konrad@gaisler.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>