Add LGS5145 SOT-23-6 buck regulator, derived from LGS5116B

https://datasheet.lcsc.com/lcsc/2304071600_Legend-Si-LGS5145_C5123971.pdf

I looked for a non-distributor datasheet, but the link on the MFR page https://www.legend-si.com/productinfo/1318197.html is only a temporary link with authkey query pararameter (doesnt work without it)