firmware-imx: bump to version 5.3

firmware-imx: bump to version 5.3

Changelog:
- Add basic epdc firmware copy to correct output path
- Move legacy epdc firmware to this package out of kernel
- VPU firmware upgrade to v3.1.1_r46070

This patch is based on the Yocto equivalent:
https://github.com/Freescale/meta-fsl-arm/commit/0fdf829

This package has been implicitely tested through gstreamer as the
plugins rely on them for vpu decoding for instance:
 # gst-launch-1.0 filesrc location=/root/tears_of_steel_1080p.webm ! \
   matroskademux ! imxvpudec ! imxipuvideosink

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>