x86: Add file names from Kconfig in descriptor/intel-me nodes in u-boot.dtsi

Since we now have the file names configurable via Kconfig for the flash
descriptor and intel-me files, add these from Kconfig in the corresponding
dts nodes.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/dts/u-boot.dtsi

@@ -17,8 +17,10 @@
 		size = <CONFIG_ROM_SIZE>;
 #ifdef CONFIG_HAVE_INTEL_ME
 		intel-descriptor {
+			filename = CONFIG_FLASH_DESCRIPTOR_FILE;
 		};
 		intel-me {
+			filename = CONFIG_INTEL_ME_FILE;
 		};
 #endif
 #ifdef CONFIG_SPL