staging: comedi: rewrite the right hand side of an assignment

This patch rewrites the right hand side of an assignment for
expressions of the form:
a = (a <op> b);
to be:
a <op>= b;
where <op> = << | >>.

This issue was detected and resolved using the following
coccinelle script:

@@
identifier i;
expression e;
@@

-i = (i >> e);
+i >>= e;

@@
identifier i;
expression e;
@@

-i = (i << e);
+i <<= e;
Signed-off-by: Aya Mahfouz <mahfouz.saif.elyazal@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/rtd520.c

@@ -579,7 +579,7 @@ static int rtd_ai_rinsn(struct comedi_device *dev,
 
 		/* read data */
 		d = readw(devpriv->las1 + LAS1_ADC_FIFO);
-		d = d >> 3;	/* low 3 bits are marker lines */
+		d >>= 3;	/* low 3 bits are marker lines */
 
 		/* convert bipolar data to comedi unsigned data */
 		if (comedi_range_is_bipolar(s, range))
@@ -616,7 +616,7 @@ static int ai_read_n(struct comedi_device *dev, struct comedi_subdevice *s,
 		}
 
 		d = readw(devpriv->las1 + LAS1_ADC_FIFO);
-		d = d >> 3;	/* low 3 bits are marker lines */
+		d >>= 3;	/* low 3 bits are marker lines */
 
 		/* convert bipolar data to comedi unsigned data */
 		if (comedi_range_is_bipolar(s, range))