Change enum identifiers for C++ compatibility

[jjw2202]

Hi,
I use the library for a C++ project. When compiling I get an error because the identifier of the enum (tmcXXXX_regaddr_t) is the same as the name of the type in the line directly before it.

In C the identifier of an enum is irrelevant (except for clarity), but in C++ it is relevant. By changing the identifier, it is also possible to use the library with a C++ compiler.
Despite the change, it is still clear that these are the addresses and that they are used with the type tmcXXXX_regaddr_t.

Since the affected files are header files, it is not possible to specifically compile the affected file with a C compiler.

jjw2202

[terjeio]

Sorry for the late reply, somehow notifications were turned off for this repo.

This change will cause issues with the EPS32 grblHAL driver since the compiler used assigns 32 bit storage to the enum. Adding a test for C++ would get around this?

#ifdef __cplusplus
enum tmc2130_regaddr {
#else
enum tmc2130_regaddr_t {
#endif

etc..