defconfig: Enable PIPE and VIRQ flags for OKL4

Enable CONFIG_OKL4_PIPE and CONFIG_OKL4_USER_VIRQ flags
to support IPC between Android VM and other VMs (non linux).

Change-Id: I7d6620416eaa9c6f03ba50a56269ed29e355bf3e
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>