b43: refuse to load unsupported firmware

[This patch is supposed to be applied in 3.1 (and maybe older) branches only.]

New kernels support newer firmware that users may try to incorrectly use
with older kernels. Display error and explain the problem in such a case

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/net/wireless/b43/main.c

@@ -2508,6 +2508,13 @@ static int b43_upload_microcode(struct b43_wldev *dev)
 		b43_print_fw_helptext(dev->wl, 1);
 		err = -EOPNOTSUPP;
 		goto error;
+	} else if (fwrev >= 598) {
+		b43err(dev->wl, "YOUR FIRMWARE IS TOO NEW. Support for "
+		       "firmware 598 and up requires kernel 3.2 or newer. You "
+		       "have to install older firmware or upgrade kernel.\n");
+		b43_print_fw_helptext(dev->wl, 1);
+		err = -EOPNOTSUPP;
+		goto error;
 	}
 	dev->fw.rev = fwrev;
 	dev->fw.patch = fwpatch;