common: add a prototype for mach_cpu_init()

Add a new file init.h with the prototype for arch_cpu_init
Add a prototype for mach_cpu_init() to avoid a warning:
no previous prototype for ‘mach_cpu_init’

It is a first step to move all the functions prototype
used during U-Boot initialization (board_f.c / board_r.c)
from common.h to init.h

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/include/common.h b/include/common.h
index 0fe9439..11e5459 100644
--- a/include/common.h
+++ b/include/common.h
@@ -62,6 +62,9 @@
 #define	TOTAL_MALLOC_LEN	CONFIG_SYS_MALLOC_LEN
 #endif
 
+/* startup functions */
+#include <init.h>
+
 /*
  * Function Prototypes
  */
@@ -464,16 +467,6 @@
 u32	cpu_dsp_mask(void);
 int	is_core_valid (unsigned int);
 
-/**
- * arch_cpu_init() - basic cpu-dependent setup for an architecture
- *
- * This is called after early malloc is available. It should handle any
- * CPU- or SoC- specific init needed to continue the init sequence. See
- * board_f.c for where it is called. If this is not provided, a default
- * version (which does nothing) will be used.
- */
-int arch_cpu_init(void);
-
 void s_init(void);
 
 int	checkcpu      (void);