MAINTAINERS: Add some RISC-V reviewers

This patch adds some active RISC-V members as reviewers to the
MAINTAINERS file.

Signed-off-by: Alistair Francis <[email protected]>
Acked-by: LIU Zhiwei <[email protected]>
Acked-by: Weiwei Li <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Bin Meng <[email protected]>
Reviewed-by: Daniel Henrique Barboza <[email protected]>
Reviewed-by: Frank Chang <[email protected]>
Message-Id: <[email protected]>

Author: alistair23

MAINTAINERS

@@ -287,6 +287,9 @@ RISC-V TCG CPUs
 M: Palmer Dabbelt <[email protected]>
 M: Alistair Francis <[email protected]>
 M: Bin Meng <[email protected]>
+R: Weiwei Li <[email protected]>
+R: Daniel Henrique Barboza <[email protected]>
+R: Liu Zhiwei <[email protected]>
 L: [email protected]
 S: Supported
 F: target/riscv/