doc: Update information on supported network adapters.

* There are no ISA PCI network adapters.
* MIPS Malta is supported with any PCI network card.
Signed-off-by: NStefan Weil <weil@mail.berlios.de>

qemu-doc.texi

@@ -166,7 +166,7 @@ PS/2 mouse and keyboard
 @item
 Floppy disk
 @item
-PCI/ISA PCI network adapters
+PCI and ISA network adapters
 @item
 Serial ports
 @item
@@ -1542,7 +1542,7 @@ PIIX4 PCI/USB/SMbus controller
 @item
 The Multi-I/O chip's serial device
 @item
-PCnet32 PCI network card
+PCI network cards (PCnet32 and others)
 @item
 Malta FPGA serial device
 @item