usb: xhci: tegra: Fix error check

usb: xhci: tegra: Fix error check

[ Upstream commit c5ce6d429ca4de913ccd5520a693c00901767c56 ]

In the function tegra_xusb_powerdomain_init(),
dev_pm_domain_attach_by_name() may return NULL in some cases,
so IS_ERR() doesn't meet the requirements. Thus fix it.

Fixes: 68a1ffbd2edd ("usb: xhci: tegra: Add genpd support")
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20220524121404.18376-1-tangbin@cmss.chinamobile.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>