net: Revert ARCNET and PHYLIB to tristate options

commit 88491d8103498a6166f70d5999902fec70924314 ("drivers/net: Kconfig
& Makefile cleanup") changed the type of these options to bool, but
they select code that could (and still can) be built as modules.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/arcnet/Kconfig

@@ -4,7 +4,7 @@
 
 menuconfig ARCNET
 	depends on NETDEVICES && (ISA || PCI || PCMCIA)
-	bool "ARCnet support"
+	tristate "ARCnet support"
 	---help---
 	  If you have a network card of this type, say Y and check out the
 	  (arguably) beautiful poetry in

drivers/net/phy/Kconfig

@@ -3,7 +3,7 @@
 #
 
 menuconfig PHYLIB
-	bool "PHY Device support and infrastructure"
+	tristate "PHY Device support and infrastructure"
 	depends on !S390
 	depends on NETDEVICES
 	help