powerpc/83xx: Fix sparse warnings in mpc836x_mds.c

This patch fixes following sparse warnings:

  CHECK   mpc836x_mds.c
mpc836x_mds.c:75:12: warning: Using plain integer as NULL pointer
mpc836x_mds.c:79:13: warning: incorrect type in assignment (different address spaces)
mpc836x_mds.c:79:13:    expected unsigned char [usertype] *static [toplevel] bcsr_regs
mpc836x_mds.c:79:13:    got void [noderef] <asn:2>*
mpc836x_mds.c:105:3: warning: incorrect type in argument 1 (different address spaces)
mpc836x_mds.c:105:3:    expected unsigned char volatile [noderef] [usertype] <asn:2>*addr
mpc836x_mds.c:105:3:    got unsigned char [usertype] *
mpc836x_mds.c:105:3: warning: incorrect type in argument 1 (different address spaces)
mpc836x_mds.c:105:3:    expected unsigned char const volatile [noderef] [usertype] <asn:2>*addr
mpc836x_mds.c:105:3:    got unsigned char [usertype] *
mpc836x_mds.c:107:3: warning: incorrect type in argument 1 (different address spaces)
mpc836x_mds.c:107:3:    expected unsigned char volatile [noderef] [usertype] <asn:2>*addr
mpc836x_mds.c:107:3:    got unsigned char [usertype] *
mpc836x_mds.c:107:3: warning: incorrect type in argument 1 (different address spaces)
mpc836x_mds.c:107:3:    expected unsigned char const volatile [noderef] [usertype] <asn:2>*addr
mpc836x_mds.c:107:3:    got unsigned char [usertype] *
mpc836x_mds.c:131:11: warning: incorrect type in argument 1 (different address spaces)
mpc836x_mds.c:131:11:    expected void volatile [noderef] <asn:2>*addr
mpc836x_mds.c:131:11:    got unsigned char [usertype] *static [toplevel] bcsr_regs

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/platforms/83xx/mpc836x_mds.c

@@ -18,6 +18,7 @@
 
 #include <linux/stddef.h>
 #include <linux/kernel.h>
+#include <linux/compiler.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/reboot.h>
@@ -55,8 +56,6 @@
 #define DBG(fmt...)
 #endif
 
-static u8 *bcsr_regs = NULL;
-
 /* ************************************************************************
  *
  * Setup the architecture
@@ -65,13 +64,14 @@ static u8 *bcsr_regs = NULL;
 static void __init mpc836x_mds_setup_arch(void)
 {
 	struct device_node *np;
+	u8 __iomem *bcsr_regs = NULL;
 
 	if (ppc_md.progress)
 		ppc_md.progress("mpc836x_mds_setup_arch()", 0);
 
 	/* Map BCSR area */
 	np = of_find_node_by_name(NULL, "bcsr");
-	if (np != 0) {
+	if (np) {
 		struct resource res;
 
 		of_address_to_resource(np, 0, &res);