Convert CONFIG_LZMA to Kconfig

This converts the following to Kconfig:
   CONFIG_LZMA

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/sheevaplug_defconfig b/configs/sheevaplug_defconfig
index 19acc7d..ac7217d 100644
--- a/configs/sheevaplug_defconfig
+++ b/configs/sheevaplug_defconfig
@@ -27,4 +27,5 @@
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
+CONFIG_LZMA=y
 CONFIG_OF_LIBFDT=y