igc: Remove MSI-X PBA Clear register

MSI-X PBA Clear register is not used. This patch comes to tidy up the
driver code.

Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

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

@@ -59,9 +59,6 @@
 #define IGC_IVAR_MISC		0x01740  /* IVAR for "other" causes - RW */
 #define IGC_GPIE		0x01514  /* General Purpose Intr Enable - RW */
 
-/* MSI-X Table Register Descriptions */
-#define IGC_PBACL		0x05B68  /* MSIx PBA Clear - R/W 1 to clear */
-
 /* RSS registers */
 #define IGC_MRQC		0x05818 /* Multiple Receive Control - RW */