manifest: default.xml: bump meta-seco-imx layer

Bump meta-seco-imx layer to add UEFI Distro support for NXP u-boot-imx
2021.04 and add GRUB 2.04 for SBC-C61.

Closes https://git.ostc-eu.org/OSTC/planning/hw-enablement/-/issues/54



Signed-off-by: Ettore Chimenti <ettore.chimenti@seco.com>