MAINTAINERS: rust: dma: add scatterlist files

Rename the "DMA MAPPING HELPERS DEVICE DRIVER API [RUST]" maintainers
entry to "DMA MAPPING & SCATTERLIST API [RUST]" and add the
corresponding scatterlist files.

Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250828133323.53311-6-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Author: Danilo Krummrich

MAINTAINERS

@@ -7238,7 +7238,7 @@ F:	include/linux/dma-mapping.h
 F:	include/linux/swiotlb.h
 F:	kernel/dma/
 
-DMA MAPPING HELPERS DEVICE DRIVER API [RUST]
+DMA MAPPING & SCATTERLIST API [RUST]
 M:	Abdiel Janulgue <abdiel.janulgue@gmail.com>
 M:	Danilo Krummrich <dakr@kernel.org>
 R:	Daniel Almeida <daniel.almeida@collabora.com>
@@ -7249,7 +7249,9 @@ S:	Supported
 W:	https://rust-for-linux.com
 T:	git https://github.com/Rust-for-Linux/linux.git alloc-next
 F:	rust/helpers/dma.c
+F:	rust/helpers/scatterlist.c
 F:	rust/kernel/dma.rs
+F:	rust/kernel/scatterlist.rs
 F:	samples/rust/rust_dma.rs
 
 DMA-BUF HEAPS FRAMEWORK