[PATCH] x86: prune redundant x64 from RMPREAD

[Shenoy, Rohan Radhesh]

AMD General

Hi Jan

> Is there a reason RMPREAD, unlike the other RMP*, requires its operands to be
> spelled out?

I do not see a reason why RMPREAD exclusively needs this. And I believe we do require an operand-less form of RMPREAD, as according to the latest APM it uses implicit operands (rax, rcx), and nowhere suggests explicitly spelling out its registers.
(AMD64 APM Vol.3, 24594 - Rev. 3.38 - July 2026 : https://docs.amd.com/v/u/en-US/24594_3.38_APM_Vol3_PUB)

Rohan