KVM: Fix ERROR: do not initialise statics to 0 or NULL in kvm_main.c

ERROR: do not initialise statics to 0 or NULL
+static int kvm_usage_count = 0;

The kvm_usage_count will be placed to .bss segment when linking, so
not need to set it to 0 here obviously.

This patch fixes this ERROR to reduce noise when checking new patches
in kvm_main.c.
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

virt/kvm/kvm_main.c

@@ -80,7 +80,7 @@ static DEFINE_RAW_SPINLOCK(kvm_count_lock);
 LIST_HEAD(vm_list);
 
 static cpumask_var_t cpus_hardware_enabled;
-static int kvm_usage_count = 0;
+static int kvm_usage_count;
 static atomic_t hardware_enable_failed;
 
 struct kmem_cache *kvm_vcpu_cache;