ARM: mark setup_machine_tags() stub as __init __noreturn

This prepares to move CONFIG_OPTIMIZE_INLINING from x86 to a common
place.  We need to eliminate potential issues beforehand.

If it is enabled for arm, Clang build results in the following modpost
warning:

  WARNING: vmlinux.o(.text+0x1124): Section mismatch in reference from the function setup_machine_tags() to the function .init.text:early_print()
  The function setup_machine_tags() references the function __init early_print().
  This is often because setup_machine_tags lacks a __init annotation or the annotation of early_print is wrong.

Link: http://lkml.kernel.org/r/20190423034959.13525-8-yamada.masahiro@socionext.comSigned-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/arm/kernel/atags.h

@@ -5,7 +5,7 @@ void convert_to_tag_list(struct tag *tags);
 const struct machine_desc *setup_machine_tags(phys_addr_t __atags_pointer,
 	unsigned int machine_nr);
 #else
-static inline const struct machine_desc *
+static inline const struct machine_desc * __init __noreturn
 setup_machine_tags(phys_addr_t __atags_pointer, unsigned int machine_nr)
 {
 	early_print("no ATAGS support: can't continue\n");