x86: braswell: cherryhill: Update dts for SPI lock down

Intel Braswell FSP requires SPI controller settings to be locked down,
let's do this in the chrryhill.dts and remove previous Kconfig option.
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

arch/x86/cpu/braswell/Kconfig

@@ -31,8 +31,4 @@ config FSP_ADDR
 	hex
 	default 0xfff20000
 
-config FSP_LOCKDOWN_SPI
-	bool
-	default y
-
 endif

arch/x86/dts/cherryhill.dts

@@ -143,6 +143,7 @@
 				#address-cells = <1>;
 				#size-cells = <0>;
 				compatible = "intel,ich9-spi";
+				intel,spi-lock-down;
 
 				spi-flash@0 {
 					#address-cells = <1>;