rcar_gen3: plat: Zero-terminate the string in unsigned_num_print()

Make sure the string generated in unsigned_num_print() is zero-terminated.
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Change-Id: Ic0ac1ebca255002522159a9152ab41991f043d05

plat/renesas/rcar/bl2_plat_setup.c

@@ -134,6 +134,7 @@ static void unsigned_num_print(unsigned long long int unum, unsigned int radix,
 
 	while (--i >= 0)
 		*string++ = num_buf[i];
+	*string = 0;
 }
 
 #if (RCAR_LOSSY_ENABLE == 1)