The fact of including both storage types (mtd and mmc) in the same 'sw-description' file is not providing any kind
of benefit. Instead, it makes the file larger, complex and harder to maintain. Additionally, most of the images
entries share the same structure and contents, changing only names and mount points. This commit simplifies the
'sw-description' file by configuring the storage type and the images to include in the SWU package at build
time, using a generic 'sw-description' template and template files for 'mmc' and 'mtd' images.
While on it, use the new 'DEY_FIRMWARE_VERSION' variable for SWU package version and fix the recipe to not include
all 'SRC_URI' files in the SWU update image, but only the required files for the update. Also, make use of variable
substitution provided by SWU class in the 'sw-description' file.
Note: SWU U-Boot update will be broken after this change. Waiting for official support with a robust implementation.
https://onedigi.atlassian.net/browse/DEL-8537https://onedigi.atlassian.net/browse/DEL-8538
Signed-off-by: David Escalona <david.escalona@digi.com>