wusb: delete double assignment

Delete successive assignments to the same location.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression i;
@@

*i = ...;
i = ...;
// </smpl>

Signed-off-by: Julia Lawall <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/wusbcore/crypto.c

···
 	WARN_ON(sizeof(ax) != sizeof(struct aes_ccm_block));
 
 	result = -ENOMEM;
-	zero_padding = sizeof(struct aes_ccm_block)
-		- blen % sizeof(struct aes_ccm_block);
 	zero_padding = blen % sizeof(struct aes_ccm_block);
 	if (zero_padding)
 		zero_padding = sizeof(struct aes_ccm_block) - zero_padding;