arm: use the correct prototype for reset_cpu function

Align reset_cpu function with the next prototypes in
sysreset.h or in cpu_func.h to solve compilation issue:

  void reset_cpu(void);

This patch solves the prototype conflict when cpu_func.h is
included.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>

arch/arm/mach-mediatek/mt8183/init.c

@@ -48,7 +48,7 @@ int mtk_soc_early_init(void)
 	return 0;
 }
 
-void reset_cpu(ulong addr)
+void reset_cpu(void)
 {
 	psci_system_reset();
 }