atm: fore200e: Do not drop const qualifier

The data member of structure firmware is const and this constness is
dropped by some cast.
This patch add some const for keeping the const information.
Signed-off-by: NLABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/atm/fore200e.c

@@ -2489,7 +2489,7 @@ static int fore200e_load_and_start_fw(struct fore200e *fore200e)
 {
     const struct firmware *firmware;
     struct device *device;
-    struct fw_header *fw_header;
+    const struct fw_header *fw_header;
     const __le32 *fw_data;
     u32 fw_size;
     u32 __iomem *load_addr;
@@ -2511,9 +2511,9 @@ static int fore200e_load_and_start_fw(struct fore200e *fore200e)
 	return err;
     }
 
-    fw_data = (__le32 *) firmware->data;
+    fw_data = (const __le32 *)firmware->data;
     fw_size = firmware->size / sizeof(u32);
-    fw_header = (struct fw_header *) firmware->data;
+    fw_header = (const struct fw_header *)firmware->data;
     load_addr = fore200e->virt_base + le32_to_cpu(fw_header->load_offset);
 
     DPRINTK(2, "device %s firmware being loaded at 0x%p (%d words)\n",