armsom boards: all branches use the same uboot

[amazingfate]

Description

Armsom is going to add mainline edge support to these two boards, and now all branches are using the same uboot config. So we do the uboot config to all branches.
Just like what we do to mixtile-blade3: bd0a09b

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• ./compile.sh uboot BOARD=armsom-w3 BRANCH=edge DEB_COMPRESS=xz
• ./compile.sh uboot BOARD=armsom-sige7 BRANCH=edge DEB_COMPRESS=xz

Checklist:

Please delete options that are not relevant.

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules