hw/char: Add Microchip PolarFire SoC MMUART emulation

Microchip PolarFire SoC MMUART is ns16550 compatible, with some
additional registers. Create a simple MMUART model built on top
of the existing ns16550 model.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <1598924352-89526-6-git-send-email-bmeng.cn@gmail.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 9641ed3..d17b08f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1321,7 +1321,9 @@
 L: qemu-riscv@nongnu.org
 S: Supported
 F: hw/riscv/microchip_pfsoc.c
+F: hw/char/mchp_pfsoc_mmuart.c
 F: include/hw/riscv/microchip_pfsoc.h
+F: include/hw/char/mchp_pfsoc_mmuart.h
 
 RX Machines
 -----------