i40e: Avoid unnecessary use of comma operator

Although it does not seem to have any untoward side-effects,
the use of ';' to separate to assignments seems more appropriate than ','.

Flagged by clang-17 -Wcomma

No functional change intended.
Compile tested only.
Signed-off-by: Simon Horman <horms@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/i40e/i40e_ethtool.c

@@ -1911,7 +1911,7 @@ static int i40e_get_eeprom(struct net_device *netdev,
 			len = eeprom->len - (I40E_NVM_SECTOR_SIZE * i);
 			last = true;
 		}
-		offset = eeprom->offset + (I40E_NVM_SECTOR_SIZE * i),
+		offset = eeprom->offset + (I40E_NVM_SECTOR_SIZE * i);
 		ret_val = i40e_aq_read_nvm(hw, 0x0, offset, len,
 				(u8 *)eeprom_buff + (I40E_NVM_SECTOR_SIZE * i),
 				last, NULL);