[POWERPC] Raise the upper limit of NR_CPUS and move the pacas into the BSS

This adds the required functionality to fill in all pacas at runtime.

With NR_CPUS=1024
text    data     bss     dec     hex filename
 137 1704032       0 1704169  1a00e9 arch/powerpc/kernel/paca.o :Before
 121 1179744  524288 1704153  1a00d9 arch/powerpc/kernel/paca.o :After

Also remove unneeded #includes from arch/powerpc/kernel/paca.c

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/paca.h b/include/asm-powerpc/paca.h
index eb61b9c..7b56444 100644
--- a/include/asm-powerpc/paca.h
+++ b/include/asm-powerpc/paca.h
@@ -108,6 +108,7 @@
 };
 
 extern struct paca_struct paca[];
+extern void initialise_pacas(void);
 
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_PACA_H */