USB: whci-hcd: add check for dma mapping error

commit f9fa1887

 upstream.

qset_fill_page_list() do not check for dma mapping errors.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>