drivers/firmware/broadcom/bcm47xx_nvram.c: fix incorrect __ioread32_copy

Commit 1f330c327900 ("drivers/firmware/broadcom/bcm47xx_nvram.c: use
__ioread32_copy() instead of open-coding") switched to use a generic
copy function, but failed to notice that the header pointer is updated
between the two copies, resulting in bogus data being copied in the
latter one.  Fix by keeping the old header pointer.

The patch fixes totally broken networking on WRT54GL router (both LAN and
WLAN interfaces fail to probe).

Fixes: 1f330c327900 ("drivers/firmware/broadcom/bcm47xx_nvram.c: use __ioread32_copy() instead of open-coding")
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Rafal Milecki <zajec5@gmail.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: <stable@vger.kernel.org>	[4.4.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/firmware/broadcom/bcm47xx_nvram.c

@@ -94,15 +94,14 @@ static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
 
 found:
 	__ioread32_copy(nvram_buf, header, sizeof(*header) / 4);
-	header = (struct nvram_header *)nvram_buf;
-	nvram_len = header->len;
+	nvram_len = ((struct nvram_header *)(nvram_buf))->len;
 	if (nvram_len > size) {
 		pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n");
 		nvram_len = size;
 	}
 	if (nvram_len >= NVRAM_SPACE) {
 		pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
-		       header->len, NVRAM_SPACE - 1);
+		       nvram_len, NVRAM_SPACE - 1);
 		nvram_len = NVRAM_SPACE - 1;
 	}
 	/* proceed reading data after header */