usb: cdnsp: blocked some cdns3 specific code

commit 18a6be67 upstream.

host.c file has some parts of code that were introduced for CDNS3 driver
and should not be used with CDNSP driver.
This patch blocks using these parts of codes by CDNSP driver.
These elements include:
- xhci_plat_cdns3_xhci object
- cdns3 specific XECP_PORT_CAP_REG register
- cdns3 specific XECP_AUX_CTRL_REG1 register

cc: stable@vger.kernel.org
Fixes: 3d829045

 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Link: https://lore.kernel.org/r/20240206104018.48272-1-pawell@cadence.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>