grub.cfg: don't handle usb at all in the main menuentry

usb support is extremely buggy in grub, and can cause boot delay issues

resources/grub/config/grub.cfg

@@ -124,7 +124,6 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 #TODO: Pick better variable name scheme than ${ddev}, or find way to make it local
 	unset ahcidev
 	unset atadev
-	unset usbdev
 	if [ (ahci?) != "(ahci?)" ]; then
 		ahcilist=(ahci*)
 		for part in ${ahcilist}; do
@@ -137,15 +136,9 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 	        	atadev="$part $atadev"
 		done
 	fi
-	if [ (usb?) != "(usb?)" ]; then
-		usblist=(usb*)
-		for part in ${usblist}; do
-	        	usbdev="$part $usbdev"
-		done
-	fi
 	set pager=0
 	echo -n "Attempting to cryptomount: "
-	for dev in ${ahcidev} ${atadev} ${lvmvol} ${usbdev}; do # what about raid?
+	for dev in ${ahcidev} ${atadev} ${lvmvol}; do # what about raid?
 		echo -n "${dev} "
 		if cryptomount "${dev}" ; then break ; fi
 	done