powerpc: Move some extern declarations from C code into headers

This also make klimit have the same type on 32-bit as on 64-bit,
namely unsigned long, and defines and initializes it in one place.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index f73d768..c98cfcc 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -279,7 +279,6 @@
 /* Warning, IO base is not yet inited */
 void __init setup_arch(char **cmdline_p)
 {
-	extern char *klimit;
 	extern void do_init_bootmem(void);
 
 	/* so udelay does something sensible, assume <= 1000 bogomips */
@@ -338,7 +337,7 @@
 	init_mm.start_code = PAGE_OFFSET;
 	init_mm.end_code = (unsigned long) _etext;
 	init_mm.end_data = (unsigned long) _edata;
-	init_mm.brk = (unsigned long) klimit;
+	init_mm.brk = klimit;
 
 	/* Save unparsed command line copy for /proc/cmdline */
 	strlcpy(saved_command_line, cmd_line, COMMAND_LINE_SIZE);