brcmfmac: Prefer DT board type over DMI board type

The introduction of support for Apple board types inadvertently changed
the precedence order, causing hybrid SMBIOS+DT platforms to look up the
firmware using the DMI information instead of the device tree compatible
to generate the board type. Revert back to the old behavior,
as affected platforms use firmwares named after the DT compatible.

Fixes: 7682de8 ("wifi: brcmfmac: of: Fetch Apple properties")

[1] https://bugzilla.opensuse.org/show_bug.cgi?id=1206697#c13

Cc: stable@vger.kernel.org
Signed-off-by: Ivan T. Ivanov <iivanov@suse.de>
Reviewed-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -79,15 +79,16 @@ void brcmf_of_probe(struct device *dev, enum brcmf_bus_type bus_type,
 	/* Apple ARM64 platforms have their own idea of board type, passed in
 	 * via the device tree. They also have an antenna SKU parameter
 	 */
-	if (!of_property_read_string(np, "brcm,board-type", &prop))
+	err = of_property_read_string(np, "brcm,board-type", &prop);
+	if (!err)
 		settings->board_type = prop;
 
 	if (!of_property_read_string(np, "apple,antenna-sku", &prop))
 		settings->antenna_sku = prop;
 
 	/* Set board-type to the first string of the machine compatible prop */
 	root = of_find_node_by_path("/");
-	if (root && !settings->board_type) {
+	if (root && err) {
 		char *board_type;
 		const char *tmp;