[LLVM][Maintainers] Step down as an NVPTX maintainer (#138936)

Author: justinfargnoli

llvm/Maintainers.md

@@ -260,8 +260,6 @@ Artem Belevich \
 [email protected] (email), [Artem-B](https://github.com/Artem-B) (GitHub) \
 Alex MacLean \
 [email protected] (email), [AlexMaclean](https://github.com/AlexMaclean) (GitHub) \
-Justin Fargnoli \
-[email protected] (email), [justinfargnoli](https://github.com/justinfargnoli) (GitHub)
 
 #### PowerPC backend
 
@@ -511,6 +509,7 @@ Peter Collingbourne ([email protected], [pcc](https://github.com/pcc)) -- LTO \
 Evan Cheng ([email protected]) -- Parts of code generator not covered by someone else \
 Jake Ehrlich ([email protected], [jakehehrlich](https://github.com/jakehehrlich)) -- llvm-objcopy and ObjCopy library \
 Hal Finkel ([email protected], [hfinkel](https://github.com/hfinkel) -- AliasAnalysis \
+Justin Fargnoli ([email protected], [justinfargnoli](https://github.com/justinfargnoli)) -- NVPTX backend \
 Renato Golin ([email protected], [rengolin](https://github.com/rengolin)) -- ARM backend \
 Venkatraman Govindaraju ([email protected], [vegovin](https://github.com/vegovin) -- Sparc backend \
 James Grosbach ([email protected]) -- MC layer \