usb: cdns3: Rids of duplicate error message

On failure, the platform_get_irq_byname prints an error message,
so patch removes error message related to this function from
core.c file.

A change was suggested during reviewing CDNSP driver by Chunfeng Yun.

Acked-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Acked-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>