staging: comedi: dt2811: remove redundant initialization of 'ns'

Variable ns is being initialized with a value that is never read, ns
is being re-assigned a new value later on. Remove the redundant
initialization.

Cleans up clang warning:
drivers/staging/comedi/drivers/dt2811.c:310:21: warning: Value stored
to 'ns' during its initialization is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/dt2811.c

@@ -307,7 +307,7 @@ static int dt2811_ai_cmd(struct comedi_device *dev,
 static unsigned int dt2811_ns_to_timer(unsigned int *nanosec,
 				       unsigned int flags)
 {
-	unsigned long long ns = *nanosec;
+	unsigned long long ns;
 	unsigned int ns_lo = COMEDI_MIN_SPEED;
 	unsigned int ns_hi = 0;
 	unsigned int divisor_hi = 0;