staging: comedi: serial2002: remove pr_err() noise in serial2002_read()

This pr_err() is just added noise, the user can't do anything about it.
Just remove it.

Since this is the only pr_level() message in the driver, also remove
the pr_fmt() macro.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/serial2002.c

@@ -31,8 +31,6 @@ Status: in development
 
 */
 
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
 #include "../comedidev.h"
 
 #include <linux/delay.h>
@@ -299,7 +297,6 @@ static struct serial_data serial2002_read(struct file *f, int timeout)
 
 		length++;
 		if (data < 0) {
-			pr_err("Failed to read serial.\n");
 			break;
 		} else if (data & 0x80) {
 			result.value = (result.value << 7) | (data & 0x7f);