cmd: fix lsblk command

Add missing includes.
Add CMD_LSBLK to sandbox_defconfig.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index 9b74e40..d43d78d 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -48,6 +48,7 @@
 CONFIG_CMD_GPT_RENAME=y
 CONFIG_CMD_IDE=y
 CONFIG_CMD_I2C=y
+CONFIG_CMD_LSBLK=y
 CONFIG_CMD_OSD=y
 CONFIG_CMD_PCI=y
 CONFIG_CMD_READ=y