rtio: workq: Select Early P4WQ threads init

Otherwise the RTIO Workqueue is not functional for devices during init.

An example of this issue is devices using SPI transfers with default
spi_rtio.

Signed-off-by: Luis Ubieda <luisf@croxel.com>
(cherry picked from commit 2ce2794987049022e1f754f87d3c9b9bd098a3a8)
1 file changed