igc: Remove duplicated IGC_RXPBS macro

This patch remove the IGC_RXPBS macro defined in line 233 since it is
already defined in line 18 with the exactly same value.
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igc/igc_regs.h

@@ -227,8 +227,6 @@
 
 #define IGC_FTQF(_n)	(0x059E0 + (4 * (_n)))  /* 5-tuple Queue Fltr */
 
-#define IGC_RXPBS	0x02404  /* Rx Packet Buffer Size - RW */
-
 /* Transmit Scheduling Registers */
 #define IGC_TQAVCTRL		0x3570
 #define IGC_TXQCTL(_n)		(0x3344 + 0x4 * (_n))