plat/arm: remove weak implemention of 'plat_arm_psci_override_pm_ops' function

In order to allow Arm platforms to override the default list of PSCI
callbacks, remove the existing weak implementation of
'plat_arm_psci_override_pm_ops' function and let all the Arm platforms
implement their own 'plat_arm_psci_override_pm_ops' function.

For platforms that support SCMI protocol, the function
'css_scmi_override_pm_ops' can be additionally used as well to
override the default PSCI callbacks.

Change-Id: If7c27468bd51a00ea9c2a3716b5894163f5a9f3c
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
diff --git a/plat/arm/board/juno/juno_pm.c b/plat/arm/board/juno/juno_pm.c
new file mode 100644
index 0000000..da2e92b
--- /dev/null
+++ b/plat/arm/board/juno/juno_pm.c
@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <plat_arm.h>
+#include <scmi.h>
+
+const plat_psci_ops_t *plat_arm_psci_override_pm_ops(plat_psci_ops_t *ops)
+{
+	return css_scmi_override_pm_ops(ops);
+}