staging:iio:rename trigger_consumer.h to indicate it is core only.

Need this out the way to create a trigger_consumer.h that actually is
for trigger consumers.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --cc drivers/staging/iio/iio_core_trigger.h
Simple merge

diff --cc drivers/staging/iio/industrialio-core.c
Simple merge

diff --cc drivers/staging/iio/industrialio-trigger.c
Simple merge