drm/msm: Select CONFIG_NVMEM

The speedbin support requires nvmem driver api. So lets explicitly
enable CONFIG_NVMEM to have this support.

Signed-off-by: Akhil P Oommen <akhilpo@codeaurora.org>
Link: https://lore.kernel.org/r/1617630433-36506-2-git-send-email-akhilpo@codeaurora.org
Signed-off-by: Rob Clark <robdclark@chromium.org>