mm/cma: change the addition of totalcma_pages in the cma_init_reserved_mem

Replace the unnecessary division calculation with cma->count when update
the value of totalcma_pages.

Link: https://lkml.kernel.org/r/20240729080431.70916-1-hao.ge@linux.devSigned-off-by: Hao Ge <gehao@kylinos.cn>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/cma.c

@@ -202,7 +202,7 @@ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 	cma->order_per_bit = order_per_bit;
 	*res_cma = cma;
 	cma_area_count++;
-	totalcma_pages += (size / PAGE_SIZE);
+	totalcma_pages += cma->count;
 
 	return 0;
 }