RFR: 8343030: RISC-V: Small assembler cleanups

[Robbin Ehn]

On Fri, 25 Oct 2024 03:07:19 GMT, Fei Yang <fyang at openjdk.org> wrote:

> Hi, please review this small code cleanups.
> 
> Witnessed some explicit type conversion to `address` is not necessary now.
> Also we can make use of `void la(Register Rd, const address addr)` where possible to simplify the code.
> This also adds one temporary register parameter for the `cmpptr` assembler routine.
> 
> Testing on linux-riscv64:
> - [ ] tier1 (release)

lgtm

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Marked as reviewed by rehn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/21699#pullrequestreview-2394708721