sfc: Clean up non-volatile memory partitioning

Move flash and EEPROM partition boundary constants into spi.h and rename
them to be consistent.

Add a comment on the partitioning.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/sfc/ethtool.c b/drivers/net/sfc/ethtool.c
index cd0d087..df0579e 100644
--- a/drivers/net/sfc/ethtool.c
+++ b/drivers/net/sfc/ethtool.c
@@ -172,10 +172,7 @@
 /* Number of ethtool statistics */
 #define EFX_ETHTOOL_NUM_STATS ARRAY_SIZE(efx_ethtool_stats)
 
-/* EEPROM range with gPXE configuration */
 #define EFX_ETHTOOL_EEPROM_MAGIC 0xEFAB
-#define EFX_ETHTOOL_EEPROM_MIN 0x800U
-#define EFX_ETHTOOL_EEPROM_MAX 0x1800U
 
 /**************************************************************************
  *
@@ -545,8 +542,8 @@
 
 	if (!spi)
 		return 0;
-	return min(spi->size, EFX_ETHTOOL_EEPROM_MAX) -
-		min(spi->size, EFX_ETHTOOL_EEPROM_MIN);
+	return min(spi->size, EFX_EEPROM_BOOTCONFIG_END) -
+		min(spi->size, EFX_EEPROM_BOOTCONFIG_START);
 }
 
 static int efx_ethtool_get_eeprom(struct net_device *net_dev,
@@ -557,7 +554,7 @@
 	size_t len;
 	int rc;
 
-	rc = falcon_spi_read(spi, eeprom->offset + EFX_ETHTOOL_EEPROM_MIN,
+	rc = falcon_spi_read(spi, eeprom->offset + EFX_EEPROM_BOOTCONFIG_START,
 			     eeprom->len, &len, buf);
 	eeprom->magic = EFX_ETHTOOL_EEPROM_MAGIC;
 	eeprom->len = len;
@@ -575,7 +572,7 @@
 	if (eeprom->magic != EFX_ETHTOOL_EEPROM_MAGIC)
 		return -EINVAL;
 
-	rc = falcon_spi_write(spi, eeprom->offset + EFX_ETHTOOL_EEPROM_MIN,
+	rc = falcon_spi_write(spi, eeprom->offset + EFX_EEPROM_BOOTCONFIG_START,
 			      eeprom->len, &len, buf);
 	eeprom->len = len;
 	return rc;