ARM: PSCI: initialize stack pointer on secondary CPUs

A proper stack is required to safely use C code in psci_arch_cpu_entry.

Fixes: 486daaa618e1 ("arm: psci: add a weak function psci_arch_cpu_entry")
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Stefan Agner <stefan.agner@toradex.com>
Acked-by: Patrick DELAUNAY <Patrick.delaunay@st.com>
Tested-by: Patrick DELAUNAY <Patrick.delaunay@st.com>

arch/arm/cpu/armv7/psci.S

@@ -331,6 +331,8 @@ ENTRY(psci_cpu_entry)
 
 	bl	_nonsec_init
 
+	bl	psci_stack_setup
+
 	bl	psci_arch_cpu_entry
 
 	bl	psci_get_cpu_id			@ CPU ID => r0