protected long getFlatOffset(int segment, long offset) {
		long res = segment;
		res <<= 4;
		res += offset;
		return res;
	}
Given a 16-bit segment and an offset, produce the flat address offset
@param segment is the segment value
@param offset is the 16-bit offset into the segment
@return the encoded flat offset
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/address/SegmentedAddressSpace.java