ARM: rmobile: Enable KSZ90X1 PHY on Salvator-X

Commit da3b9e7fd6a1 (Move PHY_MICREL and PHY_MICREL_KSZ90X1 to Kconfig)
broke ethernet support on R8A779x Salvator-X boards by disabling the
KSZ90x1 PHY in Kconfig. Reenable it.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Alexandru Gagniuc <alex.g@adaptrum.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/configs/r8a7796_salvator-x_defconfig b/configs/r8a7796_salvator-x_defconfig
index 247f878..10aa0be 100644
--- a/configs/r8a7796_salvator-x_defconfig
+++ b/configs/r8a7796_salvator-x_defconfig
@@ -25,6 +25,7 @@
 CONFIG_CLK_RENESAS=y
 CONFIG_SH_SDHI=y
 CONFIG_PHY_MICREL=y
+CONFIG_PHY_MICREL_KSZ90X1=y
 CONFIG_DM_ETH=y
 CONFIG_RENESAS_RAVB=y
 CONFIG_SCIF_CONSOLE=y