treewide: Convert CONFIG_HOSTNAME to a string option

CONFIG_HOSTNAME is defined as a "plain" preprocessor string, but every
use is couched by __stringify(...).

Hence, convert it to a proper string option.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/include/configs/x600.h b/include/configs/x600.h
index 5b2d0bf..a6fb988 100644
--- a/include/configs/x600.h
+++ b/include/configs/x600.h
@@ -113,13 +113,13 @@
 #define CONFIG_SYS_MALLOC_LEN			(8 << 20)
 #define CONFIG_SYS_LOAD_ADDR			0x00800000
 
-#define CONFIG_HOSTNAME				x600
+#define CONFIG_HOSTNAME				"x600"
 #define CONFIG_UBI_PART				ubi0
 #define CONFIG_UBIFS_VOLUME			rootfs
 
 #define	CONFIG_EXTRA_ENV_SETTINGS					\
 	"u-boot_addr=1000000\0"						\
-	"u-boot=" __stringify(CONFIG_HOSTNAME) "/u-boot.spr\0"		\
+	"u-boot=" CONFIG_HOSTNAME "/u-boot.spr\0"		\
 	"load=tftp ${u-boot_addr} ${u-boot}\0"				\
 	"update=protect off " __stringify(CONFIG_SYS_MONITOR_BASE)	\
 		" +${filesize};"					\
@@ -129,7 +129,7 @@
 		"protect on " __stringify(CONFIG_SYS_MONITOR_BASE)	\
 		" +${filesize}\0"					\
 	"upd=run load update\0"						\
-	"ubifs=" __stringify(CONFIG_HOSTNAME) "/ubifs.img\0"		\
+	"ubifs=" CONFIG_HOSTNAME "/ubifs.img\0"		\
 	"part=" __stringify(CONFIG_UBI_PART) "\0"			\
 	"vol=" __stringify(CONFIG_UBIFS_VOLUME) "\0"			\
 	"load_ubifs=tftp ${kernel_addr} ${ubifs}\0"			\
@@ -154,12 +154,12 @@
 		"saveenv;boot\0"					\
 	"ubifsargs=set bootargs ubi.mtd=ubi${boot_part} "		\
 		"root=ubi0:rootfs rootfstype=ubifs\0"			\
-	"kernel=" __stringify(CONFIG_HOSTNAME) "/uImage\0"		\
+	"kernel=" CONFIG_HOSTNAME "/uImage\0"		\
 	"kernel_fs=/boot/uImage \0"					\
 	"kernel_addr=1000000\0"						\
-	"dtb=" __stringify(CONFIG_HOSTNAME) "/"				\
-		__stringify(CONFIG_HOSTNAME) ".dtb\0"			\
-	"dtb_fs=/boot/" __stringify(CONFIG_HOSTNAME) ".dtb\0"		\
+	"dtb=" CONFIG_HOSTNAME "/"				\
+		CONFIG_HOSTNAME ".dtb\0"			\
+	"dtb_fs=/boot/" CONFIG_HOSTNAME ".dtb\0"		\
 	"dtb_addr=1800000\0"						\
 	"load_kernel=tftp ${kernel_addr} ${kernel}\0"			\
 	"load_dtb=tftp ${dtb_addr} ${dtb}\0"				\