Enable DMI table parsing on ia64.

Andi Kleen has a patch in his x86_64 tree which enables the use of i386
dmi_scan.c on x86_64. dmi_scan.c functions are being used by the
drivers/char/ipmi/ipmi_si_intf.c driver for autodetecting the ports or
memory spaces where the IPMI controllers may be found.

This patch adds equivalent changes for ia64 as to what is in the x86_64
tree. In addition, I reworked the DMI detection, such that on EFI-capable
systems, it uses the efi.smbios pointer to find the table, rather than
brute-force searching from 0xF0000. On non-EFI systems, it continues the
brute-force search.

My test system, an Intel S870BN4 'Tiger4', aka Dell PowerEdge 7250, with
latest BIOS, does not list the IPMI controller in the ACPI namespace, nor
does it have an ACPI SPMI table. Also note, currently shipping Dell x8xx
EM64T servers don't have these either, so DMI is the only method for
obtaining the address of the IPMI controller.

Signed-off-by: Matt Domsch
Acked-by: "Luck, Tony"
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds