Convert CONFIG_CMD_LZMADEC to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_LZMADEC

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/Kconfig b/arch/Kconfig
index beec00a..84da4e7 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -73,6 +73,7 @@
 	imply CMD_IO
 	imply CMD_IOTRACE
 	imply LZMA
+	imply CMD_LZMADEC
 
 config SH
 	bool "SuperH architecture"
diff --git a/cmd/Kconfig b/cmd/Kconfig
index dc81913..5ee52f6 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -438,6 +438,17 @@
 	help
 	  Display memory information.
 
+endmenu
+
+menu "Compression commands"
+
+config CMD_LZMADEC
+	bool "lzmadec"
+	select LZMA
+	help
+	  Support decompressing an LZMA (Lempel-Ziv-Markov chain algorithm)
+	  image from memory.
+
 config CMD_UNZIP
 	bool "unzip"
 	help
diff --git a/cmd/Makefile b/cmd/Makefile
index 1293d24..9ea56e9 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -127,9 +127,7 @@
 obj-$(CONFIG_CMD_UBIFS) += ubifs.o
 obj-$(CONFIG_CMD_UNIVERSE) += universe.o
 obj-$(CONFIG_CMD_UNZIP) += unzip.o
-ifdef CONFIG_LZMA
 obj-$(CONFIG_CMD_LZMADEC) += lzmadec.o
-endif
 
 obj-$(CONFIG_CMD_USB) += usb.o disk.o
 obj-$(CONFIG_CMD_FASTBOOT) += fastboot.o
diff --git a/include/configs/sandbox.h b/include/configs/sandbox.h
index b3e2c47..c62b45e 100644
--- a/include/configs/sandbox.h
+++ b/include/configs/sandbox.h
@@ -150,8 +150,6 @@
 #define CONFIG_BZIP2
 #define CONFIG_LZO
 
-#define CONFIG_CMD_LZMADEC
-
 #ifndef CONFIG_SPL_BUILD
 #define CONFIG_SYS_IDE_MAXBUS		1
 #define CONFIG_SYS_ATA_IDE0_OFFSET	0
diff --git a/scripts/config_whitelist.txt b/scripts/config_whitelist.txt
index 5b163a5..1055caf 100644
--- a/scripts/config_whitelist.txt
+++ b/scripts/config_whitelist.txt
@@ -383,7 +383,6 @@
 CONFIG_CMDLINE_EDITING
 CONFIG_CMDLINE_PS_SUPPORT
 CONFIG_CMDLINE_TAG
-CONFIG_CMD_LZMADEC
 CONFIG_CMD_MAX6957
 CONFIG_CMD_MEM
 CONFIG_CMD_MFSL