mfd: omap-usb-host: Remove PHY reset handling code

PHY reset GPIO handling will be done in the PHY driver

Signed-off-by: Roger Quadros <rogerq@ti.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>