sparc64: fix sparse warning in prom_64.c

Fix following warning:
prom_64.c:376:6: warning: symbol 'arch_find_n_match_cpu_physical_id' was not declared. Should it be static?

Add missing include to pick up prototype.
Rearrange includes to use the inverse christmas tree structure.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>