uboot-rockchip: fix ident string

Commit 79750601 ("uboot-rockchip: add new package") has added
`OpenWRT` ident string, fix it to proper `OpenWrt`.

Fixes: 79750601

 ("uboot-rockchip: add new package")
Signed-off-by: Petr Štetiar <ynezz@true.cz>

package/boot/uboot-rockchip/Makefile

@@ -42,7 +42,7 @@ define Build/Configure
 	$(call Build/Configure/U-Boot)
 
 	$(SED) 's#CONFIG_MKIMAGE_DTC_PATH=.*#CONFIG_MKIMAGE_DTC_PATH="$(PKG_BUILD_DIR)/scripts/dtc/dtc"#g' $(PKG_BUILD_DIR)/.config
-	echo 'CONFIG_IDENT_STRING=" OpenWRT"' >> $(PKG_BUILD_DIR)/.config
+	echo 'CONFIG_IDENT_STRING=" OpenWrt"' >> $(PKG_BUILD_DIR)/.config
 endef
 
 define Build/InstallDev