arm64: move jump_label_init() before parse_early_param()

While jump_label_init() was moved earlier in the boot process in
efd9e03f ("arm64: Use static keys for CPU features"), it wasn't early
enough for early params to use it.  The old state of things was as
described here...

init/main.c calls out to arch-specific things before general jump label
and early param handling:

  asmlinkage __visible void __init start_kernel(void)
  {
        ...
        setup_arch(&command_line);
        ...
        smp_prepare_boot_cpu();
        ...
        /* parameters may set static keys */
        jump_label_init();
        parse_early_param();
        ...
  }

x86 setup_arch() wants those earlier, so it handles jump label and
early param:

  void __init setup_arch(char **cmdline_p)
  {
        ...
        jump_label_init();
        ...
        parse_early_param();
        ...
  }

arm64 setup_arch() only had early param:

  void __init setup_arch(char **cmdline_p)
  {
        ...
        parse_early_param();
        ...
}

with jump label later in smp_prepare_boot_cpu():

  void __init smp_prepare_boot_cpu(void)
  {
        ...
        jump_label_init();
        ...
  }

This moves arm64 jump_label_init() from smp_prepare_boot_cpu() to
setup_arch(), as done already on x86, in preparation from early param
usage in the init_on_alloc/free() series:
https://lkml.kernel.org/r/1561572949.5154.81.camel@lca.pw

Link: http://lkml.kernel.org/r/201906271003.005303B52@keescookSigned-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/arm64/kernel/setup.c

@@ -283,6 +283,11 @@ void __init setup_arch(char **cmdline_p)
 
 	setup_machine_fdt(__fdt_pointer);
 
+	/*
+	 * Initialise the static keys early as they may be enabled by the
+	 * cpufeature code and early parameters.
+	 */
+	jump_label_init();
 	parse_early_param();
 
 	/*

arch/arm64/kernel/smp.c

@@ -420,11 +420,6 @@ void __init smp_cpus_done(unsigned int max_cpus)
 void __init smp_prepare_boot_cpu(void)
 {
 	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
-	/*
-	 * Initialise the static keys early as they may be enabled by the
-	 * cpufeature code.
-	 */
-	jump_label_init();
 	cpuinfo_store_boot_cpu();
 
 	/*