usb: gadget: aspeed_udc: validate endpoint index for ast udc

We should verify the bound of the array to assure that host
may not manipulate the index to point past endpoint array.

Found by static analysis.

Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Reviewed-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Acked-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Link: https://lore.kernel.org/r/20240625022306.2568122-1-make24@iscas.ac.cn


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