Kernel device tree got updated to use clock name as "ref" instead of
"usb2_refclk". Fix cdns3-ti.c to use the correct name.
Fixes: 70e167495a ("arm: dts: k3-j721e: Sync Linux v5.11-rc6 dts into U-Boot")
Fixes: 6239cc8c4e ("arm: dts: k3-j7200: Sync Linux v5.11-rc6 dts into U-Boot")
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>