ARM: restart: add restart hook to machine_desc record

Add a restart hook to the machine_desc record so we don't have to
populate all platforms with init_early methods to initialize the
arm_pm_restart function pointer.

Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/include/asm/mach/arch.h

@@ -45,6 +45,7 @@ struct machine_desc {
 #ifdef CONFIG_MULTI_IRQ_HANDLER
 	void			(*handle_irq)(struct pt_regs *);
 #endif
+	void			(*restart)(char, const char *);
 };
 
 /*

arch/arm/kernel/setup.c

@@ -922,6 +922,9 @@ void __init setup_arch(char **cmdline_p)
 	paging_init(mdesc);
 	request_standard_resources(mdesc);
 
+	if (mdesc->restart)
+		arm_pm_restart = mdesc->restart;
+
 	unflatten_device_tree();
 
 #ifdef CONFIG_SMP