Allocate the size of urb pointer array according to testusb's
parameter sglen, and limits the length of sglen as MAX_SGLEN
(128 currently).
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NPeter Chen <peter.chen@freescale.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>