Fixes reference to JTAG register table.

Because asciidoc doesn't support links inside literal blocks.

Minor fixes to table layout.

Still doesn't look quite right, but right aligning makes no sense for a
range.

Fixes alignment of the field name within the tables, as pointed out in

Sometimes they would wrap "Write", as pointed out in #993.

Fix tdata1 having duplicate register diagrams

Fixes a duplicate diagram for tdata1, reported in #989.

Fix asciidoc conversion for DXLEN definition.

Fix minor AsciiDoc conversion problem.

Dual-license XML files BSD-2-Clause and CC-BY-4.0

Ensure a newline at the end of registers description

Without this, the `[cols=...]` line would show up in the rendered text
(at the start of section 4.10).

The rule makes those targets from scratch now.

Fix `hartset` -> {hartsel}

Fixes #972

Also multiple identifiers must be on the same line together.

BSD-2-Clause is used so the C code generated from those files can be
used in GPLv2 open source projects (specifically, OpenOCD) and the
CC-BY-4.0 clause is the standard license for work produced by the RISC-V
Foundation.

Convert to asciidoc

Once this merges, I'll make a github release including the PDF, so the
first link will work.

Fix text overlapping in offsets in register diagrams.

bytefield really handles this very poorly, so this is a hack by moving
long offsets in a bit. Now some look a little odd with not much space
between upper and lower offset, but at least there's no actual
overlapping text anymore.

Top of some characters would sometimes be cut off otherwise.

E.g. if the field is "hit" and the offset is "XLEN-18" then the field
needs to be sized to accommodate that offset.

Remove stray $ left over from LaTeX.

Instead explicitly list both fields.

Fixes #964.

Misc asciidoc fixes.