net: smc911x: Add DM support

Add support for U-Boot DM and DT probing. Furthermore, build the
SMC911x standalone EEPROM example only for the non-DM case, as it
is not converted yet.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index bc518f2..a2587a2 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -388,11 +388,13 @@
 
 if SMC911X
 
+if !DM_ETH
 config SMC911X_BASE
 	hex "SMC911X Base Address"
 	help
 	  Define this to hold the physical address
 	  of the device (I/O space)
+endif #DM_ETH
 
 choice
 	prompt "SMC911X bus width"