libcamera: Global s/devnode/deviceNode rename

Do not use the abreviated version for members, variables and getter
methods.

Library-wise rename, no intended functional changes.

Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

test/media_device/media_device_link_test.cpp

@@ -55,7 +55,7 @@ class MediaDeviceLinkTest : public Test
 
 		if (dev_->open()) {
 			cerr << "Failed to open media device at "
-			     << dev_->devnode() << endl;
+			     << dev_->deviceNode() << endl;
 			return TestFail;
 		}