seco-mx6:defconfig: Enable SPIDEV and SPIDEVAS
Enable spidev drivers to support BLE modules on SANTVEND boards.
Depending on the revision of hardware, different drivers should be used:
- in case of v1.2 revision, it is equipped with ISP091201 BLE module which is governed by special "spidevas" driver which implements its own chip select handling.
- in case of v1.3 revision, it is equipped with Protues-III BLE module, which is governed by standard "spidev" driver.
It was decided to build the "spidevas" driver as a kernel module.