fix Z_CLEARANCE_FOR_HOMING

[DerAndere1]

Description

The CNC/miniRambo config had

#define Z_HOME_DIR 1
#define HOME_Z_FIRST
//#define Z_CLEARANCE_FOR_HOMING 4
#define Z_CLEARANCE_BETWEEN_PROBES  5

Theoretically this combo cannot work. Homing would

1. home Z to max
2. Raise Z for Z_CLEARANCE_FOR_HOMING (using fall back Z_CLEARANCE_BETWEEN_PROBES)

Maybe users of this machine always used G28 R0 instead of G28 as a workaround? Or this machine can move past the Zmax limit switch?

I now added

#define Z_CLEARANCE_FOR_HOMING 0

Benefits

prevent a crash into Z max during G28

Related Issues

#27370