platform: Remove sifive/fu540 platform

Now that SiFive HiFive Unleashed board is using the generic platform
support in OpenSBI, let's remove the old non-generic one.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

scripts/create-binary-archive.sh

@@ -95,12 +95,10 @@ build_opensbi() {
 	case "${BUILD_RISCV_XLEN}" in
 	32)
 		# Setup 32-bit platform list
-		BUILD_PLATFORM_SUBDIR=("sifive/fu540")
 		BUILD_PLATFORM_SUBDIR+=("generic")
 		;;
 	64)
 		# Setup 64-bit platform list
-		BUILD_PLATFORM_SUBDIR=("sifive/fu540")
 		BUILD_PLATFORM_SUBDIR+=("nuclei/ux600")
 		BUILD_PLATFORM_SUBDIR+=("kendryte/k210")
 		BUILD_PLATFORM_SUBDIR+=("fpga/ariane")