[arm] add ability to pass and generically read up to 4 boot args from whoever loaded lk

-Extend arch_chain_load() to pass 4 args

arch/arm/arm-m/arch.c

@@ -137,7 +137,7 @@ void arm_cm_irq_exit(bool reschedule)
 	dec_critical_section();
 }
 
-void arch_chain_load(void *entry)
+void arch_chain_load(void *entry, ulong arg0, ulong arg1, ulong arg2, ulong arg3)
 {
     PANIC_UNIMPLEMENTED;
 }