kernel-defaults: Manage the enabling/disabling of ZSTD

Linux 5.9 introduces support for ZSTD ramdisk and initrd compression,
make sure we enable/disable the relevant options when building an
initramfs enabled kernel.

Signed-off-by: Florian Fainelli <[email protected]>

include/kernel-defaults.mk

@@ -78,6 +78,7 @@ ifeq ($(CONFIG_TARGET_ROOTFS_INITRAMFS),y)
 	echo -e "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_LZO),CONFIG_INITRAMFS_COMPRESSION_LZO=y\nCONFIG_RD_LZO=y,# CONFIG_INITRAMFS_COMPRESSION_LZO is not set\n# CONFIG_RD_LZO is not set)" >> $(LINUX_DIR)/.config
 	echo -e "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_XZ),CONFIG_INITRAMFS_COMPRESSION_XZ=y\nCONFIG_RD_XZ=y,# CONFIG_INITRAMFS_COMPRESSION_XZ is not set\n# CONFIG_RD_XZ is not set)" >> $(LINUX_DIR)/.config
 	echo -e "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_LZ4),CONFIG_INITRAMFS_COMPRESSION_LZ4=y\nCONFIG_RD_LZ4=y,# CONFIG_INITRAMFS_COMPRESSION_LZ4 is not set\n# CONFIG_RD_LZ4 is not set)" >> $(LINUX_DIR)/.config
+	echo -e "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_ZSTD),CONFIG_INITRAMFS_COMPRESSION_ZSTD=y\nCONFIG_RD_STD=y,# CONFIG_INITRAMFS_COMPRESSION_ZSTD is not set\n# CONFIG_RD_ZSTD is not set)" >> $(LINUX_DIR)/.config
   endef
 else
 endif