cpumask: convert struct cpuinfo_x86's llc_shared_map to cpumask_var_t

Impact: reduce kernel memory usage when CONFIG_CPUMASK_OFFSTACK=y

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 7613950..d794d94 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -94,7 +94,7 @@
 	unsigned long		loops_per_jiffy;
 #ifdef CONFIG_SMP
 	/* cpus sharing the last level cache: */
-	cpumask_t		llc_shared_map;
+	cpumask_var_t		llc_shared_map;
 #endif
 	/* cpuid returned max cores value: */
 	u16			 x86_max_cores;