docs: networking: device drivers: convert 3com/vortex.txt to ReST

- add SPDX header;
- add a document title;
- mark code blocks and literals as such;
- mark tables as such;
- adjust identation, whitespaces and blank lines where needed;
- add to networking/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/device_drivers/index.rst

@@ -28,6 +28,7 @@ Contents:
    pensando/ionic
    stmicro/stmmac
    3com/3c509
+   3com/vortex
 
 .. only::  subproject and html
 

MAINTAINERS

@@ -147,7 +147,7 @@ Maintainers List
 M:	Steffen Klassert <klassert@kernel.org>
 L:	netdev@vger.kernel.org
 S:	Odd Fixes
-F:	Documentation/networking/device_drivers/3com/vortex.txt
+F:	Documentation/networking/device_drivers/3com/vortex.rst
 F:	drivers/net/ethernet/3com/3c59x.c
 
 3CR990 NETWORK DRIVER

drivers/net/ethernet/3com/3c59x.c

@@ -1149,7 +1149,7 @@ static int vortex_probe1(struct device *gendev, void __iomem *ioaddr, int irq,
 
 	print_info = (vortex_debug > 1);
 	if (print_info)
-		pr_info("See Documentation/networking/device_drivers/3com/vortex.txt\n");
+		pr_info("See Documentation/networking/device_drivers/3com/vortex.rst\n");
 
 	pr_info("%s: 3Com %s %s at %p.\n",
 	       print_name,
@@ -1954,7 +1954,7 @@ vortex_error(struct net_device *dev, int status)
 				   dev->name, tx_status);
 			if (tx_status == 0x82) {
 				pr_err("Probably a duplex mismatch.  See "
-						"Documentation/networking/device_drivers/3com/vortex.txt\n");
+						"Documentation/networking/device_drivers/3com/vortex.rst\n");
 			}
 			dump_tx_ring(dev);
 		}

drivers/net/ethernet/3com/Kconfig

@@ -76,7 +76,7 @@ config VORTEX
 	  "Hurricane" (3c555/3cSOHO)                           PCI
 
 	  If you have such a card, say Y here.  More specific information is in
-	  <file:Documentation/networking/device_drivers/3com/vortex.txt> and
+	  <file:Documentation/networking/device_drivers/3com/vortex.rst> and
 	  in the comments at the beginning of
 	  <file:drivers/net/ethernet/3com/3c59x.c>.