DeleteEnumVariants transform

[i509VCB]

The MSPM0 SVDs unfortunately contain enums with variants that exist on some parts, but are then not valid on other parts. I would like to delete these enum variants in a transform for some parts.

An example:

enum/SYSCTL_SYSOSCCFG_FREQ:
  bit_size: 2
  variants:
  - name: SYSOSCBASE
    value: 0
  - name: SYSOSC4M
    value: 1
  - name: SYSOSCUSER
    value: 2
  # This variant does not actually exist on the MSPM0C110x, but does exist on others
  - name: SYSOSCTURBO
    value: 3

I would think the transform to delete variants would be similar in style to !DeleteFields transform, kind of like this:

- !DeleteEnumVariants
  enums: SYSCTL_SYSOSCCFG_FREQ
  from: SYSOSCTURBO