clk: davinci: cfgchip: testing the wrong variable

There is a copy and paste bug here.  We should be testing "usb1" instead
of "usb0".

Fixes: 58e1e2d2 ("clk: davinci: cfgchip: Add TI DA8XX USB PHY clocks")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Lechner <david@lechnology.com>