target-alpha: Claim ownership.

I've been maintaining this port for a while now.

Signed-off-by: Richard Henderson <rth@twiddle.net>
diff --git a/MAINTAINERS b/MAINTAINERS
index e6f853d..35d4496 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -56,8 +56,8 @@
 Guest CPU cores (TCG):
 ----------------------
 Alpha
-M: qemu-devel@nongnu.org
-S: Orphan
+M: Richard Henderson <rth@twiddle.net>
+S: Maintained
 F: target-alpha/
 
 ARM