dmi: morph dmi_dump_ids() into dmi_format_ids() which formats into a buffer

We're goning to use DMI identification for other purposes too.  Morph
dmi_dump_ids() which is used to print DMI identification as a debug
message during boot into dmi_format_ids() which formats the same
information sans the leading "DMI:" tag into a string buffer.

dmi_present() is updated to format the information into dmi_ids_string[]
using the new function and print it with "DMI:" prefix.

dmi_ids_string[] will be used for another purpose by a future patch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>