defconfig: trinket: Enable dual isp sync support for trinket

Changes to add variable in defconfig to enable dual isp sync
support for trinket.

Signed-off-by: Meera Gande <mgande@codeaurora.org>
Signed-off-by: Abhishek Jain <abhij@codeaurora.org>
Change-Id: If21eb18a6746573450642df32b0073249ef65bc4