Classification of implicit instruction accesses as explicit accesses should be normative

[dkruckemyer-ventana]

The RERI spec has an informational comment that states:

Instruction memory accesses by a
hart are termed as implicit accesses by the Privileged specification. However for
the purposes of error reporting only the implicit accesses to data structures like
the (guest) page tables used to determine the address of the instruction to fetch are
termed as implicit accesses. The read to fetch the instruction bytes themselves are
termed as explicit reads.

Since this is reclassifying a memory access due to an instruction fetch as something different from the base spec (explicit rather than implicit), it feels like this should be made normative text rather than informational.

[ved-rivos]

Will move that block of text outside the note block.

[dkruckemyer-ventana]

Minor nit (?) as well: implicit and explicit accesses are defined in the unprivileged spec, not the priv spec.

[ved-rivos]

Updated the reference.