ARM: tegra: delete stale header content

A few function prototypes were left in header files during code re-
organization. Delete them.

Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/mach-tegra/pm.h

@@ -37,9 +37,6 @@ void tegra30_sleep_core_init(void);
 
 extern unsigned long l2x0_saved_regs_addr;
 
-void save_cpu_arch_register(void);
-void restore_cpu_arch_register(void);
-
 void tegra_clear_cpu_in_lp2(void);
 bool tegra_set_cpu_in_lp2(void);