x86/boot: Obsolete the MCA sys_desc_table

The kernel does not support the MCA bus anymroe, so mark sys_desc_table
as obsolete: remove any reference from the code together with the remaining
of MCA logic.

bloat-o-meter output:

  add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-55 (-55)
  function                                     old     new   delta
  i386_start_kernel                            128     119      -9
  setup_arch                                  1421    1375     -46

Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1437409430-8491-1-git-send-email-p.pisati@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/boot/compressed/eboot.c

@@ -1041,7 +1041,6 @@ void setup_graphics(struct boot_params *boot_params)
 struct boot_params *make_boot_params(struct efi_config *c)
 {
 	struct boot_params *boot_params;
-	struct sys_desc_table *sdt;
 	struct apm_bios_info *bi;
 	struct setup_header *hdr;
 	struct efi_info *efi;
@@ -1089,7 +1088,6 @@ struct boot_params *make_boot_params(struct efi_config *c)
 	hdr = &boot_params->hdr;
 	efi = &boot_params->efi_info;
 	bi = &boot_params->apm_bios_info;
-	sdt = &boot_params->sys_desc_table;
 
 	/* Copy the second sector to boot_params */
 	memcpy(&hdr->jump, image->image_base + 512, 512);
@@ -1118,8 +1116,6 @@ struct boot_params *make_boot_params(struct efi_config *c)
 	/* Clear APM BIOS info */
 	memset(bi, 0, sizeof(*bi));
 
-	memset(sdt, 0, sizeof(*sdt));
-
 	status = efi_parse_options(cmdline_ptr);
 	if (status != EFI_SUCCESS)
 		goto fail2;