soc: rockchip: flash_vendor_storage: Change vendor storage item size realloc strategy

Item size is calculated according to the actual space used

Change-Id: I7e4ce774a16d665a33e411991dc6dc767e1aba93
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>

Author: Jon Lin

drivers/soc/rockchip/flash_vendor_storage.c

@@ -173,8 +173,7 @@ static int flash_vendor_write(u32 id, void *pbuf, u32 size)
 				item->size = size;
 				memcpy(&p_data[item->offset], pbuf, size);
 				g_vendor->free_offset = offset + align_size;
-				g_vendor->free_size -= (align_size -
-							alloc_size);
+				g_vendor->free_size = sizeof(g_vendor->data) - g_vendor->free_offset;
 			} else {
 				memcpy(&p_data[item->offset],
 				       pbuf,