usb:chipidea:Make the function hw_alloc_repmap have a return type of void

This makes the function hw_alloc_repmap be declared to have a return
type of void now due to this particular function never returning
a error code to its caller due to this function always running
successfully to completion nor it's caller putting the return
value into a variable in order to check if a error code is passed
from the function hw_alloc_repmap when calling this function.

Signed-off-by: Nicholas Krause <xerofoify@gmail.com>