usb: dwc2: Modify dwc2_readl/writel functions prototype

Added hsotg argument to dwc2_readl/writel function prototype,
and also instead of address pass offset of register.
hsotg will contain flag field for endianness.

Also customized dwc2_set_bit and dwc2_clear_bit function for
dwc2_readl/writel functions.

Signed-off-by: Gevorg Sahakyan <sahakyan@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>