s390/zcore: Fix HSA copy length for last block

Currently always one page is copied to a user buffer for the last
HSA block in memcpy_hsa(). Now the correct length is used.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/zcore.c

@@ -127,7 +127,7 @@ static int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode)
 	}
 	if (mode == TO_USER) {
 		if (copy_to_user((__force __user void*) dest + offs, buf,
-				 PAGE_SIZE))
+				 count - offs))
 			return -EFAULT;
 	} else
 		memcpy(dest + offs, buf, count - offs);