cmd: Rename CMD_MISC to CMD_SLEEP

The "cmd/Kconfig" has a TODO description for CMD_MISC that it should
really be named as CMD_SLEEP. Change it in the whole source tree.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
diff --git a/configs/xilinx_zynqmp_mini_defconfig b/configs/xilinx_zynqmp_mini_defconfig
index c029f59..9e63533 100644
--- a/configs/xilinx_zynqmp_mini_defconfig
+++ b/configs/xilinx_zynqmp_mini_defconfig
@@ -45,7 +45,7 @@
 # CONFIG_CMD_SOURCE is not set
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_CACHE=y
-# CONFIG_CMD_MISC is not set
+# CONFIG_CMD_SLEEP is not set
 # CONFIG_PARTITIONS is not set
 CONFIG_OF_EMBED=y
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y