fsi: master-ast-cf: Fix memory leak

In case memory resources for *fw* were allocated, release them
before return.

Addresses-Coverity-ID: 1472044 ("Resource leak")
Fixes: 6a794a27daca ("fsi: master-ast-cf: Add new FSI master using Aspeed ColdFire")
Signed-off-by: Gustavo A. R. Silva <[e-mail]>
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

drivers/fsi/fsi-master-ast-cf.c

···
 	if (sig != wanted_sig) {
 		dev_err(master->dev, "Failed to locate image sig %04x in FW blob\n",
 			wanted_sig);
-		return -ENODEV;
+		rc = -ENODEV;
+		goto release_fw;
 	}
 	if (size > master->cf_mem_size) {
 		dev_err(master->dev, "FW size (%zd) bigger than memory reserve (%zd)\n",
···
 	} else {
 		memcpy_toio(master->cf_mem, data, size);
 	}
-	release_firmware(fw);
 
+release_fw:
+	release_firmware(fw);
 	return rc;
 }