usb: chipidea: remove superfluous pci_set_drvdata(pci, NULL)

As drvdata is cleared to NULL at probe failure or at removal by the driver
core, we don't have to call pci_set_drvdata(pci, NULL) any longer in each
driver.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>