CM5200: Fix missing null-termination in hostname manipulation code

Signed-off-by: Bartlomiej Sieka <tur@semihalf.com>
diff --git a/board/cm5200/cm5200.c b/board/cm5200/cm5200.c
index b74ac08..e2ab5b8 100644
--- a/board/cm5200/cm5200.c
+++ b/board/cm5200/cm5200.c
@@ -397,6 +397,7 @@
 					"operational\n");
 
 	/* set the hostname appropriate to the module we're running on */
+	hostname[0] = 0x00;
 	compose_hostname(hw_id, hostname);
 	setenv("hostname", hostname);