openhcl_boot: pass the constants into the asm!() statements.

[romank-msft]

The entry.S files use few hardcoded constansts. As of Rust 1.82, there's a new feature allowing to pass constants into the inline assembly. Use that to improve the code structure.

[smalis-msft]

The unsafes will be covered by https://github.com/microsoft/openvmm/pull/113

[romank-msft]

The unsafes will be covered by #113

Ok, updated to avoid clashing and rebasing

[romank-msft]

Will need to wait for CI to be updated to 1.82, but awesome.

Totally! Not a day went by w/o wishing that released sooner 😄