usb: dwc2: add otg_rev and otg_caps information for gadget driver

Currently the dwc2 doesn't fill in the 'otg_caps' of usb_gadget structure.
When registering a gadget device (e.g. via configfs), the
usb_otg_descriptor_init() checks the 'otg_caps' and 'otg_rev'. It defaults
to HNP and SRP bmAttributes if unspecified. There may be a mismatch with
what's being set in dwc2 params structure. This result in the descriptors
to be miss-configured in this case.

So replace 'otg_cap' bit field by 'otg_caps' structure, so hnp, srp and
otg_rev' can be configured directly in the params.
It's then provided to the gadget struct. These parameters can be tuned
for each platform. In case it's not set, it will default to current
behavior.

Also add option to setup these from the device tree by calling
of_usb_update_otg_caps(). This provides support for standard properties
such as "otg-rev", "hnp-disable" and "srp-disable" (see usb-drd.yaml).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/1634133425-25670-4-git-send-email-fabrice.gasnier@foss.st.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>