brcmfmac: Protect against reprobing

It is important to reinitialise the firmware array pointers to protect
against the case that the brcmfmac driver is reprobed without first
being unloaded.

The potential hazard was noticed while investigating
raspberrypi/firmware#1644 .

Signed-off-by: Phil Elwell <[email protected]>

Author: pelwell

drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c

@@ -651,8 +651,8 @@ static const struct brcmf_firmware_mapping sdio_fwnames[] = {
 	BRCMF_FW_ENTRY(CY_CC_43012_CHIP_ID, 0xFFFFFFFF, 43012)
 };
 
-static const struct brcmf_firmware_mapping *brcmf_sdio_fwnames = sdio_fwnames;
-static u32 brcmf_sdio_fwnames_count = ARRAY_SIZE(sdio_fwnames);
+static const struct brcmf_firmware_mapping *brcmf_sdio_fwnames;
+static u32 brcmf_sdio_fwnames_count;
 
 #define TXCTL_CREDITS	2
 
@@ -4539,6 +4539,8 @@ struct brcmf_sdio *brcmf_sdio_probe(struct brcmf_sdio_dev *sdiodev)
 
 	brcmf_dbg(INFO, "completed!!\n");
 
+	brcmf_sdio_fwnames = sdio_fwnames;
+	brcmf_sdio_fwnames_count = ARRAY_SIZE(sdio_fwnames);
 	of_fwnames = brcmf_of_fwnames(sdiodev->dev, &of_fw_count);
 	if (of_fwnames)
 		fwnames = devm_kcalloc(sdiodev->dev,