arm64: secondary_start_kernel: Remove unnecessary barrier

Remove the unnecessary smp_wmb(), which was added to make sure
that the update_cpu_boot_status() completes before we mark the
CPU online. But update_cpu_boot_status() already has dsb() (required
for the failing CPUs) to ensure the correct behavior.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Reported-by: NDennis Chen <dennis.chen@arm.com>
Signed-off-by: NSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/kernel/smp.c

@@ -264,8 +264,6 @@ asmlinkage void secondary_start_kernel(void)
 	pr_info("CPU%u: Booted secondary processor [%08x]\n",
 					 cpu, read_cpuid_id());
 	update_cpu_boot_status(CPU_BOOT_SUCCESS);
-	/* Make sure the status update is visible before we complete */
-	smp_wmb();
 	set_cpu_online(cpu, true);
 	complete(&cpu_running);