[pam]: Restrict user authentication to redfish grp

Restrict bmcweb authentication to redfish group only. This
change makes sure that user without having redfish group user
is not authenticated to query the details, and login will fail.

Tested:
1.Verified by removing the redfish group role for a valid user
and confirmed redfish session establishment fails using postman.

Change-Id: Ie0c1c94a7ac4d218a502faba1d80c7b9fc2a7ca0
Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
diff --git a/pam-webserver b/pam-webserver
index 473b922..f04b34a 100644
--- a/pam-webserver
+++ b/pam-webserver
@@ -1,5 +1,6 @@
 #%PAM-1.0
 
 auth     include  common-auth
+auth     required pam_succeed_if.so user ingroup redfish
 account  include  common-account
 password include  common-password