MAINTAINERS: Add entry for Rust cpumask API

Update the MAINTAINERS file to include the Rust abstractions for cpumask
API.

Yury has indicated that he does not wish to maintain the Rust code but
would like to be listed as a reviewer.

Signed-off-by: Viresh Kumar <[email protected]>
Reviewed-by: Yury Norov <[email protected]>

Author: vireshk

MAINTAINERS

@@ -6237,6 +6237,12 @@ L:	[email protected]
 S:	Maintained
 F:	drivers/cpuidle/cpuidle-riscv-sbi.c
 
+CPUMASK API [RUST]
+M:	Viresh Kumar <[email protected]>
+R:	Yury Norov <[email protected]>
+S:	Maintained
+F:	rust/kernel/cpumask.rs
+
 CRAMFS FILESYSTEM
 M:	Nicolas Pitre <[email protected]>
 S:	Maintained