usb: phy: qcom: Use devm_ioremap_resource()

Using devm_ioremap_resource() can make the code simpler, as it
already does the resource NULL check.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>