Added MCP41x1 and MCP41x2 digital potentiometers

I've added a series of digital potentiometers: MCP4131 MCP4132 MCP4141 MCP4142 MCP4151 MCP4152 MCP4161 MCP4162

Datasheets:

• https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/22060b.pdf
• https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/22059b.pdf