grub.cfg: skip ata/ahci according to grub_scan_disk

logic for setting it in grub.cfg will be done in the next commit

resources/grub/config/grub.cfg

@@ -28,6 +28,7 @@ fi
 set default="0"
 set timeout=10
 set pager=1
+set grub_scan_disk="both"
 
 keymap usqwerty
 function try_user_config {
@@ -75,8 +76,13 @@ function search_isolinux {
 	echo # Insert newline
 }
 menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o' {
+
+	if [ "${grub_scan_disk}" != "ata" ]; then
 		search_grub ahci
+	fi
+	if [ "${grub_scan_disk}" != "ahci" ]; then
 		search_grub ata
+	fi
 
 	# grub device enumeration is very slow, so checks are hardcoded
 
@@ -97,8 +103,12 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 	unset atadev
 	for i in 11 10 9 8 7 6 5 4 3 2 1 0; do
 		for part in 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1; do
+			if [ "${grub_scan_disk}" != "ata" ]; then
 				ahcidev="(ahci${i},${part}) ${ahcidev}"
+			fi
+			if [ "${grub_scan_disk}" != "ahci" ]; then
 				atadev="(ata${i},${part}) ${atadev}"
+			fi
 		done
 	done
 
@@ -117,6 +127,7 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 
 	search_grub crypto
 
+	if [ "${grub_scan_disk}" != "ata" ]; then
 		# Last resort, if all else fails
 		set root=ahci0,1
 		for p in / /boot/; do
@@ -127,7 +138,9 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 				fi
 			fi
 		done
+	fi
 
+	if [ "${grub_scan_disk}" != "ahci" ]; then
 		# Last resort (for setups that use IDE instead of SATA)
 		set root=ata0,1
 		for p in / /boot/; do
@@ -138,6 +151,7 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 				fi
 			fi
 		done
+	fi
 
 	true # Prevent pager requiring to accept each line instead of whole screen
 }