[etherfabric] Avoid unused variable warning in gcc 4.6

Reported-by: Ralph Giles <giles@thaumas.net>
Tested-by: Ralph Giles <giles@thaumas.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/etherfabric.c

 clear_b0_fpga_memories ( struct efab_nic *efab)
 {
 	efab_oword_t blanko, temp;
-	efab_dword_t blankd;
 	int offset; 
 
 	EFAB_ZERO_OWORD ( blanko );
-	EFAB_ZERO_DWORD ( blankd );
 
 	/* Clear the address region register */
 	EFAB_POPULATE_OWORD_4 ( temp,
 falcon_probe_nic_variant ( struct efab_nic *efab, struct pci_device *pci )
 {
 	efab_oword_t altera_build, nic_stat;
-	int is_pcie, fpga_version;
+	int fpga_version;
 	uint8_t revision;
 
 	/* PCI revision */
 	/* MAC and PCI type */
 	falcon_read ( efab, &nic_stat, FCN_NIC_STAT_REG );
 	if ( efab->pci_revision == FALCON_REV_B0 ) {
-		is_pcie = 1;
 		efab->phy_10g = EFAB_OWORD_FIELD ( nic_stat, FCN_STRAP_10G );
 	}
 	else if ( efab->is_asic ) {
-		is_pcie = EFAB_OWORD_FIELD ( nic_stat, FCN_STRAP_PCIE );
 		efab->phy_10g = EFAB_OWORD_FIELD ( nic_stat, FCN_STRAP_10G );
 	}
 	else {
 		int minor = EFAB_OWORD_FIELD ( altera_build,  FCN_VER_MINOR );
-		is_pcie = 0;
 		efab->phy_10g = ( minor == 0x14 );
 	}
 }