defconfig: enable hypervisor call support on 8994 debug config

Enable hypervisor call (hvc) support so other drivers can use the
hvc api to avail hypervisor services.

Change-Id: Id9e20c4668dbf7b189b6d6f4866e64a32f9369d2
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>