Kernel is built with target-feature=+soft-float (no SSE), but the
upstream ProcUptime code used f64 in format!() which requires SSE
register return. This caused a build error:
error: src/scheme/proc.rs:2047:32: ... SSE register return with
SSE disabled
Replace the f64 arithmetic with integer math (seconds.milliseconds)
to make the kernel buildable on the redoxer cross-toolchain.
vasilito
fac69f9d03