Add ResizeEnums transform

[i509VCB]

The MSPM0 SVDs have enums which are larger than needed. An example of this is the STAT register for the MSPM0C110x where after eliminating variants not present in the technical manual manual (see #58), there are 2 bits of unused space which are reserved.

Example:

  # STAT used on C110x has a field size of 2 bits
  - !ResizeEnums
    enum: STAT
    bit_size: 2

Along side resizing the enum, uses of the enum have the bit size changed as well. The transform also validates the following:

• The new size is not 0 (why would you do this?)
• That the enum variants can be represented in the range of valid values for the bit size (e.g., no value of 4 for a 2-bit enum with a maximum value of 3)
• If the enum has grown in size, that no field overlaps are created as a result of the resize.