x86: Remove quotation mark in CONFIG_HOSTNAME

CONFIG_HOSTNAME is an environment varible, so that quotation mark
is not needed.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

include/configs/x86-common.h

@@ -217,7 +217,7 @@
 
 /* Default environment */
 #define CONFIG_ROOTPATH		"/opt/nfsroot"
-#define CONFIG_HOSTNAME		"x86"
+#define CONFIG_HOSTNAME		x86
 #define CONFIG_BOOTFILE		"bzImage"
 #define CONFIG_LOADADDR		0x1000000