[media] easycap: streamline the code

change statements of types
	if (err)
		return err
	else
		do something

and
	if (ok)
		do something
	else
		return err

into

	if (err)
		return err

	do something

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>