target/riscv: add a MAINTAINERS entry for XThead* extension support

The XThead* extensions are maintained by T-Head and VRULL.
Adding a point of contact from both companies.

Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Message-Id: <20230131202013.2541053-15-christoph.muellner@vrull.eu>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index fa10eca..96e25f6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -295,6 +295,14 @@
 F: linux-user/host/riscv32/
 F: linux-user/host/riscv64/
 
+RISC-V XThead* extensions
+M: Christoph Muellner <christoph.muellner@vrull.eu>
+M: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
+L: qemu-riscv@nongnu.org
+S: Supported
+F: target/riscv/insn_trans/trans_xthead.c.inc
+F: target/riscv/xthead*.decode
+
 RISC-V XVentanaCondOps extension
 M: Philipp Tomsich <philipp.tomsich@vrull.eu>
 L: qemu-riscv@nongnu.org