This unbreaks support for USB devices, which do not have a board_type
to create an alt_path out of and thus were running into a NULL
dereference.

Fixes: 5ff013914c62 ("brcmfmac: firmware: Allow per-board firmware binaries")
Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Hector Martin <redacted>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
index 1001c8888bfe..63821856bbe1 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c

@@ -599,6 +599,9 @@ static char *brcm_alt_fw_path(const char *path, const char *board_type)
 	char alt_path[BRCMF_FW_NAME_LEN];
 	char suffix[5];
 
+	if (!board_type)
+		return NULL;
+
 	strscpy(alt_path, path, BRCMF_FW_NAME_LEN);
 	/* At least one character + suffix */
 	if (strlen(alt_path) < 5)

-- 
2.33.0