grub.cfg: scan lvm volumes last

lvm/* is slow to resolve in grub, on some machines,
because grub enumeration is very slow in general.

however, many people will install distros with any
number of lvm configurations, so we should try to
support them.

Signed-off-by: Leah Rowe <leah@libreboot.org>

config/grub/config/grub.cfg

@@ -142,6 +142,10 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 
 	search_grub crypto
 
+	for vol in lvm/* ; do
+		try_user_config "${vol}"
+	done
+
 	if [ "${grub_scan_disk}" != "ata" ]; then
 		# Last resort, if all else fails
 		set root=ahci0,1