Add vishwa as Maintainer

I have implemented the first version of phosphor-watchdog
and have started to follow the changes in gerrit / mailing list

Change-Id: Iac9a135bf1447e62d3513c2be82139c78ca0d4f4
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 959923c..9fae6f1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -44,3 +44,4 @@
 
 M:  William Kennington <wak@google.com> <wak-work!>
 M:  Deepak Kodihalli <dkodihal@linux.vnet.ibm.com> <dkodihal!>
+M:  Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com> <vishwa!>