riscv: reorder setMR to align to enum

Aligning the order of setMR writes to the enum order avoids having
to prove that the operations commute.

Signed-off-by: Gerwin Klein <gerwin.klein@data61.csiro.au>

Convert license tags to SPDX identifiers

This commit also converts our own copyright headers to directly use
SPDX, but leaves all other copyright header intact, only adding the
SPDX ident. As far as possible this commit also merges multiple
Data61 copyright statements/headers into one for consistency.

style: consistently attach return type

Add attach-return-type to astyle

style: consistently align pointer with name

Run astyle with align-pointer=name

riscv: fix style

SELFOUR-1276: set PrefetchFault MR for riscv

This was being tracked in the fault_t, but not set as part of the
message to the user.

[SELFOUR-1156] RISC-V Port

Experimental release that supports both RV32 and RV64