Move #ifdef(CONFIG_DISPLAY_CPUINFO) from caller to callee

- When CONFIG_DISPLAY_CPUINFO is not enabled,
   print_cpuinfo() should be defined as an empty function
   in a header, include/common.h

 - Remove #ifdef CONFIG_DISPLAY_CPUINFO .. #endif
   from caller, common/board_f.c and arch/arm/lib/board.c

 - Remove redundant prototypes in arch/arm/lib/board.c,
   arch/arm/include/asm/arch-am33x/sys_proto.h and
   board/nokia/rx51/rx51.h, keeping the one in include/common.h

 - Add #ifdef CONFIG_DISPLAY_CPUINFO to the func definition
   where it is missing

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

include/common.h

@@ -304,7 +304,14 @@ extern ulong monitor_flash_len;
 int mac_read_from_eeprom(void);
 extern u8 __dtb_dt_begin[];	/* embedded device tree blob */
 int set_cpu_clk_info(void);
+#if defined(CONFIG_DISPLAY_CPUINFO)
 int print_cpuinfo(void);
+#else
+static inline int print_cpuinfo(void)
+{
+	return 0;
+}
+#endif
 int update_flash_size(int flash_size);
 
 /**