usb: gadget: renesas_usb3: validate endpoint index in standard request handlers

usb: gadget: renesas_usb3: validate endpoint index in standard request handlers

The GET_STATUS and SET/CLEAR_FEATURE handlers extract the endpoint
number from the host-supplied wIndex without any sort of validation.
Fix this up by validating the number of endpoints actually match up with
the number the device has before attempting to dereference a pointer
based on this math.

This is just like what was done in commit ee0d382feb44 ("usb: gadget:
aspeed_udc: validate endpoint index for ast udc") for the aspeed driver.

Fixes: 746bfe63bba3 ("usb: gadget: renesas_usb3: add support for Renesas USB3.0 peripheral controller")
Cc: stable <stable@kernel.org>
Assisted-by: gregkh_clanker_t1000
Link: https://patch.msgid.link/2026040647-sincerity-untidy-b104@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>