TMC updates, capture LCD changes

[teemuatlut]

In an effort to crack down on some bugs

• If a user has an LCD configured, capture the LCD shadow variables any time a write happens. This will keep the variables always up to date when viewed (or modified) either from the LCD menu or from gcode commands. Initiating the shadow variables at boot time is no longer necessary.
• TMCMarlin class is now aware of the AxisEnum axis ID number. For now it is only used for determining the steps per mm setting from planner array, but it may become useful later on.
• MONITOR_DRIVER_STATUS now works with TMC2208 SW Serial communication as well. This was an artificial limitation as it is considerable slower than the HW counterpart, but perhaps not too slow after all.
• Removed many unnecessary functions and references with planner spmm as arguments. The same functionality can be handled inside the class which is now aware of the planner array and indexing.
• Addressed a compile warning about some unused functions in tmc_util.

---

Current state: Final maybe

[teemuatlut]

WIP: Need to account for Distinct E factors for Axis Enum Index

[teemuatlut]

Ended up restructuring much of the stepper indirection but it's now a bit more concise with 200 fewer lines of code. The vast majority of it is TMC stuff anyway.

[rst00]

After 1c86fbc marlin is not compiling with TMC and disabled HYBRID_THRESHOLD because get_pwm_thrs is undefined.

[teemuatlut]

Can you attach your config files. I'm not getting an error and a quick search shows that all get_pwm_thrs are methods inside the class and everywhere are accessed through the stepper objects.

EDIT: Found the issue from tmc_util.cpp. Updating soon.