arm: tegra20: bct: add missing <vsprintf.h>

Fixes implicit declaration of function 'hextoul'

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
diff --git a/arch/arm/mach-tegra/tegra20/bct.c b/arch/arm/mach-tegra/tegra20/bct.c
index e155b98..b647b6b 100644
--- a/arch/arm/mach-tegra/tegra20/bct.c
+++ b/arch/arm/mach-tegra/tegra20/bct.c
@@ -6,6 +6,7 @@
 
 #include <command.h>
 #include <log.h>
+#include <vsprintf.h>
 #include <asm/arch-tegra/crypto.h>
 #include "bct.h"
 #include "uboot_aes.h"