msm: ipa: Prevent deletion of the default route rule

The first APPS default routing table rule is installed
at the IPA driver initialization. To prevent routing
exception, this rule cannot be deleted by user application.
This change prevents deleting this rule.

Change-Id: Ia27434fd24a15fea5956018a1271b11bbe227df7
CRs-fixed: 2165859
Signed-off-by: Ghanim Fodi <gfodi@codeaurora.org>