usb: dwc3: Use the correct speed macros for DSTS/DCFG

Correct the use of the DWC3_DSTS_XXX_SPEED and DWC3_DCFG_XXX_SPEED
macros. The wrong set of macros were being used in a few places.

This is only a cosmetic change as the values for both sets are
identical.

Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>