kernel: simplify SetInitramfs compression ALGO config setup

Simplify SetInitramfs compression ALGO config setup by using Makefile
foreach.
While at it also make it more readable.

Link: https://github.com/openwrt/openwrt/pull/12959
Signed-off-by: Christian Marangi <[email protected]>

include/kernel-defaults.mk

@@ -80,13 +80,10 @@ endif
 	echo "# CONFIG_INITRAMFS_FORCE is not set" >> $(2)/.config
   endif
 	echo "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_NONE),CONFIG_INITRAMFS_COMPRESSION_NONE=y,# CONFIG_INITRAMFS_COMPRESSION_NONE is not set)" >> $(2)/.config
-	echo -e "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_GZIP),CONFIG_INITRAMFS_COMPRESSION_GZIP=y\nCONFIG_RD_GZIP=y,# CONFIG_INITRAMFS_COMPRESSION_GZIP is not set\n# CONFIG_RD_GZIP is not set)" >> $(2)/.config
-	echo -e "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_BZIP2),CONFIG_INITRAMFS_COMPRESSION_BZIP2=y\nCONFIG_RD_BZIP2=y,# CONFIG_INITRAMFS_COMPRESSION_BZIP2 is not set\n# CONFIG_RD_BZIP2 is not set)" >> $(2)/.config
-	echo -e "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_LZMA),CONFIG_INITRAMFS_COMPRESSION_LZMA=y\nCONFIG_RD_LZMA=y,# CONFIG_INITRAMFS_COMPRESSION_LZMA is not set\n# CONFIG_RD_LZMA is not set)" >> $(2)/.config
-	echo -e "$(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)" >> $(2)/.config
-	echo -e "$(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)" >> $(2)/.config
-	echo -e "$(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)" >> $(2)/.config
-	echo -e "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_ZSTD),CONFIG_INITRAMFS_COMPRESSION_ZSTD=y\nCONFIG_RD_ZSTD=y,# CONFIG_INITRAMFS_COMPRESSION_ZSTD is not set\n# CONFIG_RD_ZSTD is not set)" >> $(2)/.config
+	$(foreach ALGO,GZIP BZIP2 LZMA LZO XZ LZ4 ZSTD, \
+		$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_$(ALGO)),\
+			echo -e "CONFIG_INITRAMFS_COMPRESSION_$(ALGO)=y\nCONFIG_RD_$(ALGO)=y" >> $(2)/.config;,\
+			echo -e "# CONFIG_INITRAMFS_COMPRESSION_$(ALGO) is not set\n# CONFIG_RD_$(ALGO) is not set" >> $(2)/.config;))
   endef
 else
 endif