fpga: fpga-mgr: wrap the status() op

An FPGA manager is not required to provide a status() op.
Add a wrapper consistent with the other op wrappers.
Move the op check to the wrapper.
Default to 0, no errors to report.

[mdf@kernel.org: Reworded first line]
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>

drivers/fpga/fpga-mgr.c

@@ -25,6 +25,13 @@ struct fpga_mgr_devres {
 	struct fpga_manager *mgr;
 };
 
+static inline u64 fpga_mgr_status(struct fpga_manager *mgr)
+{
+	if (mgr->mops->status)
+		return mgr->mops->status(mgr);
+	return 0;
+}
+
 static inline int fpga_mgr_write(struct fpga_manager *mgr, const char *buf, size_t count)
 {
 	if (mgr->mops->write)
@@ -434,10 +441,7 @@ static ssize_t status_show(struct device *dev,
 	u64 status;
 	int len = 0;
 
-	if (!mgr->mops->status)
-		return -ENOENT;
-
-	status = mgr->mops->status(mgr);
+	status = fpga_mgr_status(mgr);
 
 	if (status & FPGA_MGR_STATUS_OPERATION_ERR)
 		len += sprintf(buf + len, "reconfig operation error\n");