libcamera: v4l2_subdevice: Remove unnecessary variable

`model` is not used, so remove it.

Fixes: 5d2aad02e8 ("libcamera: add model() for retrieving model name in V4L2Subdevice")
Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/libcamera/v4l2_subdevice.cpp

@@ -1728,7 +1728,6 @@ const std::string &V4L2Subdevice::model()
 	std::regex i2cRegex{ " [0-9]+-[0-9a-f]{4}" };
 	std::smatch match;
 
-	std::string model;
 	if (std::regex_search(entityName, match, i2cRegex))
 		model_ = entityName.substr(0, entityName.find(' '));
 	else