target-sparc: fix up niagara machine

Remove the Niagara stub implementation from sun4u.c and add a machine,
compatible with Legion simulator from the OpenSPARC T1 project.

The machine uses the firmware supplied with the OpenSPARC T1 project,
http://download.oracle.com/technetwork/systems/opensparc/OpenSPARCT1_Arch.1.5.tar.bz2
in the directory S10image/, and is able to boot the supplied Solaris 10 image.

Note that for compatibility with the naming conventions for SPARC machines
the new machine name is lowercase niagara.

Signed-off-by: Artyom Tarasenko <atar4qemu@gmail.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
diff --git a/MAINTAINERS b/MAINTAINERS
index 54588e5..b5ebfab 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -725,6 +725,13 @@
 F: hw/sparc64/sun4u.c
 F: pc-bios/openbios-sparc64
 
+Sun4v
+M: Artyom Tarasenko <atar4qemu@gmail.com>
+S: Maintained
+F: hw/sparc64/sun4v.c
+F: hw/timer/sun4v-rtc.c
+F: include/hw/timer/sun4v-rtc.h
+
 Leon3
 M: Fabien Chouteau <chouteau@adacore.com>
 S: Maintained
@@ -1098,12 +1105,6 @@
 F: include/hw/nvram/chrp_nvram.h
 F: tests/prom-env-test.c
 
-sun4v RTC
-M: Artyom Tarasenko <atar4qemu@gmail.com>
-S: Maintained
-F: hw/timer/sun4v-rtc.c
-F: include/hw/timer/sun4v-rtc.h
-
 Subsystems
 ----------
 Audio