tc: make --help easier to read

System commands usually list arguments to parameters after the argument
name. They also separate required from optional arguments visually
rather than tagging them.

This way it's more clear whether options require a parameter and what it
is. Lines are more concise, and there's less boilerplate to scan
through.

Also align with spaces so the help "renders" the same on every machine.

Also change the double `shift` command to `shift 2` to save on a line
for each option as it is getting long with boilerplate.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>