fpga: fix naked return error from linter

golangci-lint version < v1.53.0 used nakedret linter that did not check
return values in conditionals. That got changed in v1.53.0 and some
of our code starts failing because of naked returns from conditionals.

Update the code to get nakedret linter passing.

Signed-off-by: Hyeongju Johannes Lee <hyeongju.lee@intel.com>

cmd/fpga_tool/fpga_tool.go

@@ -118,7 +118,7 @@ func validateFlags(cmd, bitstream, device string, port uint) error {
 func installBitstream(fname string, dryRun, force, quiet bool) (err error) {
 	info, err := bitstream.Open(fname)
 	if err != nil {
-		return
+		return err
 	}
 	defer info.Close()
 
@@ -129,7 +129,7 @@ func installBitstream(fname string, dryRun, force, quiet bool) (err error) {
 
 		if dryRun {
 			fmt.Println("Dry-run: no copying performed")
-			return
+			return nil
 		}
 	}
 
@@ -285,21 +285,21 @@ func printFpgaPort(f fpga.Port, quiet bool) (err error) {
 
 	pci, err := f.GetPCIDevice()
 	if err != nil {
-		return
+		return err
 	}
 
 	printPCIeInfo(pci, quiet)
 
 	fme, err := f.GetFME()
 	if err != nil {
-		return
+		return err
 	}
 
 	fmt.Printf("FME Name                         : %s\n", fme.GetName())
 
 	num, err := f.GetPortID()
 	if err != nil {
-		return
+		return err
 	}
 
 	fmt.Printf("Port Id                          : %d\n", num)

pkg/fpga/dfl_linux.go

@@ -403,7 +403,7 @@ func (f *DflPort) GetFME() (fme FME, err error) {
 
 	pci, err := f.GetPCIDevice()
 	if err != nil {
-		return
+		return nil, err
 	}
 
 	if pci.PhysFn != nil {
@@ -417,17 +417,17 @@ func (f *DflPort) GetFME() (fme FME, err error) {
 	}
 
 	if err = readFilesInDirectory(fileMap, filepath.Join(pci.SysFsPath, dflFpgaFmeGlobPCI)); err != nil {
-		return
+		return nil, err
 	}
 
 	realDev, err := filepath.EvalSymlinks(filepath.Join("/dev/char", dev))
 	if err != nil {
-		return
+		return nil, err
 	}
 
 	fme, err = NewDflFME(realDev)
 	if err != nil {
-		return
+		return nil, err
 	}
 
 	f.FME = fme

pkg/fpga/intel_fpga_linux.go

@@ -408,7 +408,7 @@ func (f *IntelFpgaPort) GetFME() (fme FME, err error) {
 
 	pci, err := f.GetPCIDevice()
 	if err != nil {
-		return
+		return nil, err
 	}
 
 	if pci.PhysFn != nil {
@@ -421,17 +421,17 @@ func (f *IntelFpgaPort) GetFME() (fme FME, err error) {
 		"dev": &dev,
 	}
 	if err = readFilesInDirectory(fileMap, filepath.Join(pci.SysFsPath, intelFpgaFmeGlobPCI)); err != nil {
-		return
+		return nil, err
 	}
 
 	realDev, err := filepath.EvalSymlinks(filepath.Join("/dev/char", dev))
 	if err != nil {
-		return
+		return nil, err
 	}
 
 	fme, err = NewIntelFpgaFME(realDev)
 	if err != nil {
-		return
+		return nil, err
 	}
 
 	f.FME = fme