references: remove RISC-V platform specification

The work on the 'RISC-V platform specification' was abandoned.
There is no ratified version. Remove the reference.

Signed-off-by: Heinrich Schuchardt <[email protected]>

Author: xypron

source/chapter1-about.rst

@@ -174,8 +174,6 @@ easily meet the stricter BBR requirements.
 By definition, all BBR compliant systems are also EBBR compliant, but the
 converse is not true.
 
-This specification is referenced by RISC-V platform specification [RVPLTSPC]_.
-
 Conventions Used in this Document
 =================================
 

source/references.rst

@@ -55,8 +55,6 @@ Bibliography
    <https://uefi.org/sites/default/files/resources/UEFI_Spec_Final_2.11.pdf>`_,
    December 2024, `UEFI Forum <https://uefi.org/>`_
 
-.. [RVPLTSPC] `RISC-V Platform specification <https://github.com/riscv/riscv-platform-specs>`_
-
 .. [RVSBISPC] `RISC-V Supervisor Binary Interface specification
    <https://docs.riscv.org/reference/platform-software/sbi/_attachments/riscv-sbi.pdf>`_