Commit 31d8ff94 ("meta-digi-arm: u-boot: Update recipes with new u-boot version")
updates the license checksum for the new u-boot_2019.04 recipe, however this
license file is different for the other u-boot versions.
This commit reverts this change and includes the updated checksum only for the
new u-boot_2019.04 recipe.
Signed-off-by: Arturo Buzarra <arturo.buzarra@digi.com>