fpga: machxo2-spi: Return an error on failure

[ Upstream commit 3433173 ]

Earlier successes leave 'ret' in a non error state, so these errors are
not reported. Set ret to -EINVAL before going to the error handler.

This addresses two issues reported by smatch:
drivers/fpga/machxo2-spi.c:229 machxo2_write_init()
  warn: missing error code 'ret'

drivers/fpga/machxo2-spi.c:316 machxo2_write_complete()
  warn: missing error code 'ret'

[mdf@kernel.org: Reworded commit message]
Fixes: 88fb3a0 ("fpga: lattice machxo2: Add Lattice MachXO2 support")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/fpga/machxo2-spi.c

@@ -225,8 +225,10 @@ static int machxo2_write_init(struct fpga_manager *mgr,
 		goto fail;
 
 	get_status(spi, &status);
-	if (test_bit(FAIL, &status))
+	if (test_bit(FAIL, &status)) {
+		ret = -EINVAL;
 		goto fail;
+	}
 	dump_status_reg(&status);
 
 	spi_message_init(&msg);
@@ -313,6 +315,7 @@ static int machxo2_write_complete(struct fpga_manager *mgr,
 	dump_status_reg(&status);
 	if (!test_bit(DONE, &status)) {
 		machxo2_cleanup(mgr);
+		ret = -EINVAL;
 		goto fail;
 	}