genwqe: Remove unused parameter in some functions

This is a clean-up patch, no functional changes intended.

It removes the unused parameter of type "struct ddcb_requ*" from
the functions genwqe_user_vmap() and genwqe_user_vunmap().

Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>