[POWERPC] Add _nmask_and_or_msr() declartion to asm-powerpc/system.h

Prevents miscellaneous users from declaring it locally.
Signed-off-by: Jon Loeliger <jdl@freecale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c

@@ -53,8 +53,6 @@
 
 #define MPC7448HPC2_PCI_CFG_PHYS 0xfb000000
 
-extern void _nmask_and_or_msr(unsigned long nmask, unsigned long or_val);
-
 int mpc7448_hpc2_exclude_device(struct pci_controller *hose,
 				u_char bus, u_char devfn)
 {

include/asm-powerpc/system.h

@@ -169,6 +169,8 @@ extern int do_page_fault(struct pt_regs *, unsigned long, unsigned long);
 extern void bad_page_fault(struct pt_regs *, unsigned long, int);
 extern int die(const char *, struct pt_regs *, long);
 extern void _exception(int, struct pt_regs *, int, unsigned long);
+extern void _nmask_and_or_msr(unsigned long nmask, unsigned long or_val);
+
 #ifdef CONFIG_BOOKE_WDT
 extern u32 booke_wdt_enabled;
 extern u32 booke_wdt_period;