Fix checkpatch.pl issue:
CHECK: usleep_range is preferred over udelay; see
       Documentation/timers/timers-howto.txt
Replace the udelay() with usleep_range() with a reasonable upper limit.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
        if (val != devpriv->last_ctreg) {
                outb(val, dev->iobase + ADQ12B_CTREG);
                devpriv->last_ctreg = val;
-               udelay(50);     /* wait for the mux to settle */
+               usleep_range(50, 100);  /* wait for the mux to settle */
        }
 
        val = inb(dev->iobase + ADQ12B_ADLOW);  /* trigger A/D */