Windows OSL: Remove obsolete reference to memory list field.

The LinkOffset field has been removed. Caused a compile problem
if the local cache is not used. (Windows utilities only.)
Fix possible buffer overflow during a field unit read operation.

Can only happen under these conditions:
1) The DSDT version is 1, meaning integers are 32-bits.
2) The field is between 33 and 64 bits long.

In this case, a buffer is created for the field, but it will
be written beyond the end because it is less than 64 bits long.