sound/oss/sb_ess.c: 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 <julia@diku.dk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/oss/sb_ess.c

@@ -1721,7 +1721,6 @@ printk (KERN_INFO "FKS: es_rec_set_recmask mask = %x\n", mask);
 				left  = value & 0x000000ff;
 				right = (value & 0x0000ff00) >> 8;
 			} else {				/* Turn it off (3)  */
-				left  = 0;
 				left  = 0;
 				right = 0;
 			}