Arm: dts: socfpga: Remove invalid property from chose node

Finding bitstream from cff-file is no longer valid after bitstream is built
into FIT image and loaded by generic firmware loader. Remove cff-file
as this is legacy implementation from A10 downstream.
Signed-off-by: NTien Fong Chee <tien.fong.chee@intel.com>

arch/arm/dts/socfpga_arria10_socdk_sdmmc_handoff.dtsi

@@ -16,10 +16,6 @@
 	#size-cells = <1>;
 	model = "SOCFPGA Arria10 Dev Kit";	/* Bootloader setting: uboot.model */
 
-	chosen {
-		cff-file = "socfpga.rbf";	/* Bootloader setting: uboot.rbf_filename */
-	};
-
 	/* Clock sources */
 	clocks {
 		#address-cells = <1>;