phy: bcm-sr-pcie: Change operation when PIPEMUX=1

When PIPEMIX=1, change the operation from 2x8 EP to 1x8 EP + 1x8 RC.

Signed-off-by: Qingmin Liu <qingmin.liu@broadcom.com>
Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>