defconfig: sm8150: Enable RPMSG GLINK spi transport

The RPMSG GLINK spi transport enables communication to the wdsp
processor over a spi bus. The glink spi driver receives notifications
about processor status from a component manager and internally handles
SSR.

Change-Id: Ie0b67e87c06dd50a37a9993c7dee19e5918f09e4
Signed-off-by: Chris Lew <clew@codeaurora.org>