disk/ doc/ lib_*/ and tools/: Remove lingering references to CFG_CMD_* symbols.

Fixed some broken instances of "#ifdef CMD_CFG_IDE" too.
Those always evaluated TRUE, and thus were always compiled
even when IDE really wasn't defined/wanted.

Signed-off-by: Jon Loeliger <jdl@freescale.com>
diff --git a/doc/README.usb b/doc/README.usb
index 41f76f4..b3bcb91 100644
--- a/doc/README.usb
+++ b/doc/README.usb
@@ -73,8 +73,8 @@
 
 Config Switches:
 ----------------
-CFG_CMD_USB	    enables basic USB support and the usb command
-CONFIG_USB_UHCI	    defines the lowlevel part.A lowlevel part must be defined if
-		    using CFG_CMD_USB
+CONFIG_CMD_USB	    enables basic USB support and the usb command
+CONFIG_USB_UHCI	    defines the lowlevel part.A lowlevel part must be defined
+		    if using CONFIG_CMD_USB
 CONFIG_USB_KEYBOARD enables the USB Keyboard
 CONFIG_USB_STORAGE  enables the USB storage devices