x86/cpu: Track legacy CPU model data only on 32-bit kernels

struct cpu_dev's c_models is only ever set inside CONFIG_X86_32
conditionals (or code that's being built for 32-bit only), so
there's no use of reserving the (empty) space for the model
names in a 64-bit kernel.

Similarly, c_size_cache is only used in the #else of a
CONFIG_X86_64 conditional, so reserving space for (and in one
case even initializing) that field is pointless for 64-bit
kernels too.

While moving both fields to the end of the structure, I also
noticed that:

 - the c_models array size was one too small, potentially causing
   table_lookup_model() to return garbage on Intel CPUs (intel.c's
   instance was lacking the sentinel with family being zero), so the
   patch bumps that by one,

 - c_models' vendor sub-field was unused (and anyway redundant
   with the base structure's c_x86_vendor field), so the patch deletes it.

Also rename the legacy fields so that their legacy nature stands out
and comment their declarations.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/5265036802000078000FC4DB@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/cpu/umc.c

@@ -11,8 +11,8 @@
 static const struct cpu_dev umc_cpu_dev = {
 	.c_vendor	= "UMC",
 	.c_ident	= { "UMC UMC UMC" },
-	.c_models = {
-		{ .vendor = X86_VENDOR_UMC, .family = 4, .model_names =
+	.legacy_models	= {
+		{ .family = 4, .model_names =
 		  {
 			  [1] = "U5D",
 			  [2] = "U5S",