xhci: tegra: Prevent error pointer dereference

xhci: tegra: Prevent error pointer dereference

During initialization, the host and super-speed power domains will
contain an ERR_PTR() encoded error code rather than being NULL. To
avoid a crash, use a !IS_ERR_OR_NULL() condition during cleanup.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Fixes: 6494a9ad86de ("usb: xhci: tegra: Add genpd support")
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>