riscv: cap_get_archCapIsPhysical unreachable case

The spec expects cap_get_archCapIsPhysical to return false for the
unreachable case. While we could prove that the case is unreachable in
all contexts the function is called, it needs fewer (=no) preconditions
when it provides a safe default instead.

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

riscv: use same vm_rights as x86 for caps

Rights on frame caps differ somewhat between architectures, not entirely
in consistent ways. An example is handling write-only frame rights,
where riscv departs from x86. The vm_rights enumeration is not dictated
by hardware, hence we should strive towards consistency.

This change removes VMWriteOnly and makes riscv vm_rights and rights
masking match x86, to facilitate verification of riscv with reduced
proof changes. It does for the time being remove the ability for
write-only frames on riscv.

Signed-off-by: Rafal Kolanski <rafal.kolanski@data61.csiro.au>

riscv: use word_t rather than "unsigned int"

For other platforms, word_t is used for passing length and size
parameters and adapts to 32 and 64-bit platforms appropriately.
The riscv platforms stands out by using "unsigned int" unlike the
others.

Reduce usage of "unsigned int" to match the other 64-bit verification
target platform, x86 64-bit.

Signed-off-by: Rafal Kolanski <rafal.kolanski@data61.csiro.au>

replacing all ifndef with pargma once

All the kernel header files now use pargma once rather than the ifndef,
as the pre-processed C files do not change while header files
are protected with pargma once. This will also solve any naming issues
caused by ifndef.

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: pte_t type in asid_pool

The asids in risc-v only point to pte_t and so this does not need to be a void* type

riscv: Implement Arch_isCapRevocable

riscv: Remove VMNoAccess mapping type

A frame cannot be mapped without any access permissions, as this encoding is used to
represent a page table mapping.

riscv: VMWriteOnly vm right

Unlike other architectures riscv supports write only mappings and it simplifies management
of cap rights to actually support it.

[SELFOUR-1156] RISC-V Port

Experimental release that supports both RV32 and RV64