MAINTAINERS: add entry for the pin-init crate

Add maintainers entry for the `pin-init` crate.

This crate is already being maintained by me, but until now there
existed two different versions: the version inside of the kernel tree
and a user-space version at [1]. The previous patches synchronized these
two versions to reduce the maintenance burden. In order to keep them
synchronized from now on, separate the maintenance from other Rust code.

Link: https://github.com/Rust-for-Linux/pin-init [1]
Signed-off-by: Benno Lossin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

Author: y86-dev

MAINTAINERS

@@ -20737,6 +20737,19 @@ T:	git https://github.com/Rust-for-Linux/linux.git alloc-next
 F:	rust/kernel/alloc.rs
 F:	rust/kernel/alloc/
 
+RUST [PIN-INIT]
+M:	Benno Lossin <[email protected]>
+L:	[email protected]
+S:	Maintained
+W:	https://rust-for-linux.com/pin-init
+B:	https://github.com/Rust-for-Linux/pin-init/issues
+C:	zulip://rust-for-linux.zulipchat.com
+P:	rust/pin-init/CONTRIBUTING.md
+T:	git https://github.com/Rust-for-Linux/linux.git pin-init-next
+F:	rust/kernel/init.rs
+F:	rust/pin-init/
+K:	\bpin-init\b|pin_init\b|PinInit
+
 RXRPC SOCKETS (AF_RXRPC)
 M:	David Howells <[email protected]>
 M:	Marc Dionne <[email protected]>