ADIv5: use new DAP ops for DP read/write

ADIv5: use new DAP ops for DP read/write

Make ADIv5 internals use the two new transport-neutral calls for reading
and writing DP registers.  Also,  bugfix some of their call sites to
handle the fault returns, instead of ignoring them.

Remove the old JTAG-specific calls, using their code as the bodies
of the JTAG-specific implementation for the new methods.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>