imx6: rename target to 'imx'

This is first step in migrating to a generic i.MX target which in the
next steps will also get divided into arch-specific subtargets.

In the result, this will make it possible to support, within a single
target, also other modern NXP i.MX families, like the i.MX 7, i.MX 8
or recently introduced i.MX 9.

Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>

target/linux/imx/base-files/lib/preinit/79_move_config

@@ -0,0 +1,21 @@
+. /lib/imx.sh
+. /lib/functions.sh
+. /lib/upgrade/common.sh
+
+move_config() {
+	local board=$(board_name)
+
+	case "$board" in
+	toradex,apalis_imx6q-eval |\
+	toradex,apalis_imx6q-ixora |\
+	toradex,apalis_imx6q-ixora-v1.1 )
+		if [ -b $(bootpart_from_uuid) ]; then
+			apalis_mount_boot
+			[ -f "/boot/$BACKUP_FILE" ] && mv -f "/boot/$BACKUP_FILE" /
+			umount /boot
+		fi
+		;;
+	esac
+}
+
+boot_hook_add preinit_mount_root move_config