efi: Unify DMI setup code over the arm/arm64, ia64 and x86 architectures

All architectures (arm/arm64, ia64 and x86) do the same here, so unify
the code.

Note: We do not need to call dump_stack_set_arch_desc() in case of
!dmi_available. Both strings, dmi_ids_string and dump_stack_arch_
desc_str are initialized zero and thus nothing would change.

Signed-off-by: Robert Richter <rrichter@marvell.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190328193429.21373-5-ard.biesheuvel@linaro.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>