[FR] Add support for G60/G61 with NUM_AXES >= 4

[DerAndere1]

Description

Add support for G60/G61 with NUM_AXES >= 4 to https://github.com/MarlinFirmware/Marlin/tree/bugfix-2.1.x

Steps to Reproduce

1. See motion.h line 58.

Expected behavior:

Working G60/G61 with NUM_AXES >= 4

Actual behavior:

See motion.h line 58.

Additional Information

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