Remove priv-callback support

priv-callback is deprecated as this privilege is applicable
only to IPMI modem callback, which will not be supported in OpenBmc.
In order to avoid confusion with this role, the same has been
deprecated. Refer https://gerrit.openbmc-project.xyz/#/c/openbmc/docs/+/26839/

Tested:
1. Verified user management works as expected
2. Verified existing user with priv-callback is rolled as no-acess user.

Change-Id: I6be40f0719e7cfb20c42e1f1383b0fb264aba147
Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
diff --git a/recipes-phosphor/users/phosphor-user-manager_git.bb b/recipes-phosphor/users/phosphor-user-manager_git.bb
index 4ccf0c3..8a2971c 100644
--- a/recipes-phosphor/users/phosphor-user-manager_git.bb
+++ b/recipes-phosphor/users/phosphor-user-manager_git.bb
@@ -23,8 +23,8 @@
 USERADD_PACKAGES = "${PN} phosphor-ldap"
 DBUS_PACKAGES = "${USERADD_PACKAGES}"
 # add groups needed for privilege maintenance
-GROUPADD_PARAM_${PN} = "priv-admin; priv-operator; priv-user; priv-callback "
-GROUPADD_PARAM_phosphor-ldap = "priv-admin; priv-operator; priv-user; priv-callback "
+GROUPADD_PARAM_${PN} = "priv-admin; priv-operator; priv-user "
+GROUPADD_PARAM_phosphor-ldap = "priv-admin; priv-operator; priv-user "
 
 DBUS_SERVICE_${PN} += "xyz.openbmc_project.User.Manager.service"
 FILES_phosphor-ldap += " \