sensorhub: use system revison rather than defconfig for variants

Change-Id: I66889432883c1ca1e07784f34aa3bcdbd2cdf21d

Conflicts:
	drivers/sensorhub/factory/accel_mpu6500.c
	drivers/sensorhub/factory/gyro_mpu6500.c
	drivers/sensorhub/factory/light_cm3320.c
	drivers/sensorhub/factory/temphumidity_shtc1.c