sandbox: capsule: remove capsule related configs

The capsule update testing is carried out only on the sandbox and
sandbox_flattree variants. Remove the capsule update related configs
from the other sandbox variants. This ensures that the capsule files
are generated only on variants which are used for the feature's
testing.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
4 files changed