rocker: add stolen break in rocker_io_readl (PHYS_PORT_COUNT)

This fixes a regression caused by:
4db8907b704e7edc441a6d9b66df6a25be12328f "rocker: Implement DMA API"

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Scott Feldman <sfeldma@cumulusnetworks.com>