staging: comedi: ni_pcimio: remove unused variable 'serial_number'

The struct 'ni_private' holds the variable 'serial_number' which post
assignment is never used. Remove the variable and code pertaining to
obtaining its value.

As a side note, this also fixes the following sparse error:
drivers/staging/comedi/drivers//ni_pcimio.c:1229:32: warning: incorrect type in assignment (different base types)
drivers/staging/comedi/drivers//ni_pcimio.c:1229:32:    expected restricted __be32 [usertype] serial_number
drivers/staging/comedi/drivers//ni_pcimio.c:1229:32:    got unsigned int
Signed-off-by: Karthik Nayak <Karthik.188@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ni_pcimio.c

@@ -1202,8 +1202,6 @@ static void m_series_init_eeprom_buffer(struct comedi_device *dev)
 	resource_size_t daq_phys_addr;
 	static const int Start_Cal_EEPROM = 0x400;
 	static const unsigned int window_size = 10;
-	static const int serial_number_eeprom_offset = 0x4;
-	static const int serial_number_eeprom_length = 0x4;
 	unsigned int old_iodwbsr_bits;
 	unsigned int old_iodwbsr1_bits;
 	unsigned int old_iodwcr1_bits;
@@ -1221,13 +1219,6 @@ static void m_series_init_eeprom_buffer(struct comedi_device *dev)
 	writel(0x1 | old_iodwcr1_bits, mite->mmio + MITE_IODWCR_1);
 	writel(0xf, mite->mmio + 0x30);
 
-	BUG_ON(serial_number_eeprom_length > sizeof(devpriv->serial_number));
-	for (i = 0; i < serial_number_eeprom_length; ++i) {
-		char *byte_ptr = (char *)&devpriv->serial_number + i;
-		*byte_ptr = ni_readb(dev, serial_number_eeprom_offset + i);
-	}
-	devpriv->serial_number = be32_to_cpu(devpriv->serial_number);
-
 	for (i = 0; i < M_SERIES_EEPROM_SIZE; ++i)
 		devpriv->eeprom_buffer[i] = ni_readb(dev, Start_Cal_EEPROM + i);
 

drivers/staging/comedi/drivers/ni_stc.h

@@ -1031,7 +1031,6 @@ struct ni_private {
 
 	unsigned short ai_fifo_buffer[0x2000];
 	u8 eeprom_buffer[M_SERIES_EEPROM_SIZE];
-	__be32 serial_number;
 
 	struct mite *mite;
 	struct mite_channel *ai_mite_chan;