This Kconfig entry should declare a dependency on OF

Fixes: 6076967a ("phy: qualcomm: usb: Add SuperSpeed PHY driver")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lkml.org/lkml/2020/11/13/414Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Link: https://lore.kernel.org/r/20201113151225.1657600-2-bryan.odonoghue@linaro.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>