ide-tape: remove redundant variable buffer_size

Variable buffer_size is being assigned but is never used hence it is
redundant and can be removed.

Cleans up clang warning:
warning: variable 'buffer_size' set but not used [-Wunused-but-set-variable]
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/ide/ide-tape.c

@@ -1746,7 +1746,6 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
 {
 	unsigned long t;
 	int speed;
-	int buffer_size;
 	u16 *ctl = (u16 *)&tape->caps[12];
 
 	ide_debug_log(IDE_DBG_FUNC, "minor: %d", minor);
@@ -1781,7 +1780,6 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
 		*ctl /= 2;
 		tape->buffer_size = *ctl * tape->blk_size;
 	}
-	buffer_size = tape->buffer_size;
 
 	/* select the "best" DSC read/write polling freq */
 	speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);