defconfig: sm6150: Enable missing networking options

Android Kernel Net Testing requires additional configuration options
to work properly. Enable the following:
        SYN_COOKIES
        INET_UDP_DIAG
        IP_SCTP
        INET_SCTP_DIAG

Change-Id: I69f15a203a62dafd19631b1865f30a0049c62e29
Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>
Signed-off-by: Chinmay Agarwal <chinagar@codeaurora.org>