usb: dwc2: Set core parameters to default values

Initialize the core parameters to their default, auto-detected values.

Remove all the previous dwc2_set_param* methods. Most of what this code
is doing is handling defaults for "not set" values and other trivial
checks. The checking can be simplified and will be done in a later
commit.

This allows us to change only those parameters that won't work with
default settings. It also allows us to use non-int parameters.

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