brcmfmac: fix CLM load error for legacy chips when user helper is enabled

For legacy chips without CLM blob files, kernel with user helper function
returns -EAGAIN when we request_firmware(), and then driver got failed
when bringing up legacy chips. We expect the CLM blob file for legacy chip
is not existence in firmware path, but the -ENOENT error is transferred to
-EAGAIN in firmware_class.c with user helper.
Because of that, we continue with CLM data currently present in firmware
if getting error from doing request_firmware().

Cc: stable@vger.kernel.org # v4.15.y
Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Wright Feng <wright.feng@cypress.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -182,12 +182,9 @@ static int brcmf_c_process_clm_blob(struct brcmf_if *ifp)
 
 	err = request_firmware(&clm, clm_name, dev);
 	if (err) {
-		if (err == -ENOENT) {
-			brcmf_dbg(INFO, "continue with CLM data currently present in firmware\n");
-			return 0;
-		}
-		brcmf_err("request CLM blob file failed (%d)\n", err);
-		return err;
+		brcmf_info("no clm_blob available(err=%d), device may have limited channels available\n",
+			   err);
+		return 0;
 	}
 
 	chunk_buf = kzalloc(sizeof(*chunk_buf) + MAX_CHUNK_LEN - 1, GFP_KERNEL);