config: android: enable CONFIG_SECCOMP

config: android: enable CONFIG_SECCOMP

As of Android N, SECCOMP is required. Without it, we will get
mediaextractor error:

E /system/bin/mediaextractor: libminijail: prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER): Invalid argument

Link: http://lkml.kernel.org/r/20160908185934.18098-3-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>