treewide: Move CONFIG_PHY_MARVELL to Kconfig

The CONFIG_PHY_MARVELL has already been migrated to Kconfig (some boards
already had it in their Kconfig), but had not been moved for older
boards.

Move it to the defconfigs for all boards.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/configs/k2g_evm_defconfig b/configs/k2g_evm_defconfig
index 9cb4f2e..306901f 100644
--- a/configs/k2g_evm_defconfig
+++ b/configs/k2g_evm_defconfig
@@ -42,6 +42,7 @@
 CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_PHYLIB=y
+CONFIG_PHY_MARVELL=y
 CONFIG_PHY_MICREL=y
 CONFIG_DM_ETH=y
 CONFIG_REMOTEPROC_TI_POWER=y