It’s a “period spelling”, if you would.
Margaret Mitchell’s novel Gone with the Wind was published in 1936. The lickered up spelling of liquored up first appeared during the Prohibition, but dried up afterwards.
Here’s a Google N-gram demonstrating that:
Indeed, her publication date of 1936 puts her right in the middle of the period that saw the most use of lickered up.
The verb liquor up can be transitive or intransitive, and is now considered slang. The OED gives these senses:
- To supply with liquor to drink; to ply with liquor. Also to liquor up. Now slang.
- intr. (slang.) To drink alcoholic liquor. Also to liquor up.
One citation they provide is:
- 1890 Boy’s Own Paper 11 Jan. 227/3
I’ve been liquored up and stroked down till I feel about as shaky as our friend Hugh there.
So you could liquor someone up if you felt like it. Probably best not to write about lickering them up these days, though. It’s pretty thoroughly non-standard a spelling these days.