ARM64: configs: Add Platform MHU in defconfig

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 920f1e8..e82bad9 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -396,6 +396,7 @@
 CONFIG_HWSPINLOCK_QCOM=y
 CONFIG_MAILBOX=y
 CONFIG_ARM_MHU=y
+CONFIG_PLATFORM_MHU=y
 CONFIG_HI6220_MBOX=y
 CONFIG_ARM_SMMU=y
 CONFIG_QCOM_SMEM=y