sparc: fix sparse warnings in arch/sparc/prom for 32 bit build

Fix following sparse warnings:
arch/sparc/prom/bootstr_32.c:32:35: warning: Using plain integer as NULL pointer
arch/sparc/prom/memory.c:61:13: warning: symbol 'prom_meminit' was not declared. Should it be static?
arch/sparc/prom/misc_32.c:74:1: error: symbol 'prom_halt' redeclared with different type (originally declared at arch/sparc/include/asm/oplib_32.h:67) - different modifiers
arch/sparc/prom/ranges.c:16:26: warning: symbol 'promlib_obio_ranges' was not declared. Should it be static?
arch/sparc/prom/ranges.c:17:5: warning: symbol 'num_obio_ranges' was not declared. Should it be static?
arch/sparc/prom/ranges.c:39:1: warning: symbol 'prom_adjust_ranges' was not declared. Should it be static?
arch/sparc/prom/ranges.c:69:13: warning: symbol 'prom_ranges_init' was not declared. Should it be static?
arch/sparc/prom/tree_32.c:286:22: warning: Using plain integer as NULL pointer
arch/sparc/prom/tree_32.c:286:38: warning: Using plain integer as NULL pointer

None of the warnings indicated any serious issues.

We are now sparse clean for 32 bit build in arch/sparc/prom.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/prom/ranges.c b/arch/sparc/prom/ranges.c
index 541fc82..0857aa9 100644
--- a/arch/sparc/prom/ranges.c
+++ b/arch/sparc/prom/ranges.c
@@ -13,8 +13,8 @@
 #include <asm/types.h>
 #include <asm/system.h>
 
-struct linux_prom_ranges promlib_obio_ranges[PROMREG_MAX];
-int num_obio_ranges;
+static struct linux_prom_ranges promlib_obio_ranges[PROMREG_MAX];
+static int num_obio_ranges;
 
 /* Adjust register values based upon the ranges parameters. */
 static void
@@ -35,7 +35,7 @@
 	}
 }
 
-void
+static void
 prom_adjust_ranges(struct linux_prom_ranges *ranges1, int nranges1,
 		   struct linux_prom_ranges *ranges2, int nranges2)
 {