smbios: address build warning

include display_options.h to address build warning:
lib/smbios.c: In function ‘smbios_update_version’:
lib/smbios.c:305:9: warning: implicit declaration of function ‘print_buffer’
[-Wimplicit-function-declaration]
         print_buffer((ulong)ptr, ptr, 1, old_len + 1, 0);
         ^~~~~~~~~~~~

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/lib/smbios.c b/lib/smbios.c
index a36d4b4..defb6b4 100644
--- a/lib/smbios.c
+++ b/lib/smbios.c
@@ -7,6 +7,7 @@
 
 #define LOG_CATEGORY	LOGC_BOARD
 
+#include <display_options.h>
 #include <dm.h>
 #include <env.h>
 #include <linux/stringify.h>