KVM: s390: fix calculation of idle_mask array size

We need BITS_TO_LONGS, not sizeof(long) to calculate
the correct size.

idle_mask is a bitmask, each bit representing the state
of a cpu. The desired outcome is an array of unsigned long
fields that can fit KVM_MAX_VCPUS bits. We should not use
sizeof(long) which returnes the size in bytes, but BITS_TO_LONGS

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/include/asm/kvm_host.h

@@ -213,8 +213,7 @@ struct kvm_s390_float_interrupt {
 	struct list_head list;
 	atomic_t active;
 	int next_rr_cpu;
-	unsigned long idle_mask[(KVM_MAX_VCPUS + sizeof(long) - 1)
-				/ sizeof(long)];
+	unsigned long idle_mask[BITS_TO_LONGS(KVM_MAX_VCPUS)];
 	unsigned int irq_count;
 };