This commit creates file structure for register cache related
functions.
Specifically:
* `riscv_reg.h` -- general interface to registers. Safe to use after
register cache initialization is successful.
* `riscv_reg_impl.h` -- helper functions to use while implementing
register cache initialization.
* `riscv_reg.c` -- definitions of functions from `riscv_reg.h` and
`riscv_reg_impl.h`.
* `riscv-011_reg.h` -- register cache interface specific to 0.11
targets.
* `riscv-013_reg.h` -- register cache interface specific to 0.13+
targets.
* `riscv-011/0.13.h` -- version-specific methods used to access
registers. Will be extended as needed once other functionality (not
related to register access) is separated (e.g. DM/DTM specific stuff).
Change-Id: I7918f78d0d79b97188c5703efd0296660e529f2a
Signed-off-by: Evgeniy Naydanov <evgeniy.naydanov@syntacore.com>
3883b03aaa