SWPROT-8953: ci: github: Disable armhf as not building in qemu

For some reason armhf is not buidling despite the tricks in helper script:

    [5/1594] Running: cargo build target unify_build
    error: failed to determine package fingerprint for build script for
    unify_attribute_poll v0.1.0
    (/.../unifysdk-src/components/unify_attribute_poll)
    (...)
    "Value too large for defined data type; class=Os (2)"

Amazingly no problems observed on arm64 (with same rustup versions)

Not only on github because ot is reproducable locally.

Not sure problem is related to symlinks,
issues to track at qemu, glibc, linux ext4...

Relate-to: https://gitlab.com/qemu-project/qemu/-/issues/263
Relate-to: https://bugzilla.kernel.org/show_bug.cgi?id=205957
Relate-to: https://sourceware.org/bugzilla/show_bug.cgi?id=23960
Relate-to: https://sourceware.org/bugzilla/show_bug.cgi?id=23960
Relate-to: https://bugs.launchpad.net/qemu/+bug/1805913
Relate-to: rust-lang/cargo#8719
Relate-to: rust-lang/cargo#9881
Relate-to: rust-lang/cargo#9545 (comment)
Origin: #21
Signed-off-by: Philippe Coval <philippe.coval@silabs.com>

Author: rzr

.github/workflows/build-rootfs.yml

@@ -14,7 +14,7 @@ jobs:
         arch:
           - amd64
           - arm64
-          - armhf
+          # - armhf # TODO Enable when supported
     steps:
       - uses: actions/checkout@v4.1.1
         with: