s2io: fix documentation about intr_type

The documentation for intr_type module parameter of the s2io driver is
not consistent with the code. The comments in drivers/net/s2io.c are
OK, but Documentation/networking/s2io.txt is wrong.

Pointed out by Andrew Hecox.
Signed-off-by: NMichal Schmidt <mschmidt@redhat.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Documentation/networking/s2io.txt

@@ -83,9 +83,9 @@ Valid range: Limited by memory on system
 Default: 30 
 
 e. intr_type
-Specifies interrupt type. Possible values 1(INTA), 2(MSI), 3(MSI-X)
-Valid range: 1-3
-Default: 1 
+Specifies interrupt type. Possible values 0(INTA), 2(MSI-X)
+Valid values: 0, 2
+Default: 2
 
 5.  Performance suggestions
 General: