Tunnel Term Attributes validation condition for MP2P and MP2MP types

[mholankar]

For Tunnel Termination Tables - for MP2P type, we want to be able to provide the dst IP+ mask & src IP. Also for MP2MP type, made sure dst IP and src IP attributes are allowed for the type

This is the Pull Request to make this fix. https://github.com/opencomputeproject/SAI/pull/1799.

However, this PR seems to cause a test failure in sairedis.

main::test_brcm_acl_limit: Fresh start Killing syncd Flushing redis Starting syncd Replay BCM56971B0/acl_limit.rec terminate called after throwing an instance of 'std::runtime_error' what(): :- replay: failed to execute api: c: SAI_STATUS_MANDATORY_ATTRIBUTE_MISSING player BCM56971B0/acl_limit.rec: exitcode: 134: FAIL: BCM56971B0.pl

It seems that for tunnel types SAI_TUNNEL_TERM_TABLE_ENTRY_TYPE_P2MP, the SAI_TUNNEL_TERM_TABLE_ENTRY_ATTR_SRC_IP attribute is missing for the test cases.