vxworks: fixed cpu enable using PSCI on armv8

Without armv8_setup_psci register VBAR_EL3 is not set up property which
makes SMC calls jump to invalid location.

smp_kick_all_cpus is required to make slave cpus leave gic_wait_for_interrupt.
Without this they will never pursue booting process.

Fix was applied to the two ways of booting VxWorks: bootvx and bootm commands.

This implementation is very similar to what is done in boot_jump_linux
in arch/arm/lib/bootm.c file.

Tested on VxWorks 7 release SR0520 2017-12-08 Intel Stratix 10 SX SoC
Development Kit board.

Signed-off-by: Vasyl Vavrychuk <vasyl.vavrychuk@globallogic.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/cmd/elf.c b/cmd/elf.c
index 0387964..19479bb 100644
--- a/cmd/elf.c
+++ b/cmd/elf.c
@@ -369,6 +369,11 @@
 	printf("## Starting vxWorks at 0x%08lx ...\n", addr);
 
 	dcache_disable();
+#if defined(CONFIG_ARM64) && defined(CONFIG_ARMV8_PSCI)
+	armv8_setup_psci();
+	smp_kick_all_cpus();
+#endif
+
 #ifdef CONFIG_X86
 	/* VxWorks on x86 uses stack to pass parameters */
 	((asmlinkage void (*)(int))addr)(0);