configs: bcmstb: Disable networking support

Silence the "Driver Model for Ethernet drivers" migration warning for
the bcm7445 and bcm7260 ports, neither of which supports networking yet.

Signed-off-by: Thomas Fitzsimmons <fitzsim@fitzsim.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/bcm7260_defconfig b/configs/bcm7260_defconfig
index f25659d..d1b0530 100644
--- a/configs/bcm7260_defconfig
+++ b/configs/bcm7260_defconfig
@@ -27,6 +27,7 @@
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+# CONFIG_NET is not set
 CONFIG_DM_MMC=y
 CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_BCMSTB=y