libcamera: Remove StreamRoles alias

Now that `Camera::generateConfiguration()` takes a `libcamera::Span`
of `StreamRole`, remove the `StreamRoles` type, which was an alias
to `std::vector<libcamera::StreamRole>`.

The removal has two reasons:
 - it is no longer strictly necessary,
 - its presence may suggest that that is the preferred (or correct)
   way to build/pass a list of `StreamRole`.

Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
[Kieran: Fix small checkstyle report on roles initialiser]
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/stream.cpp

@@ -436,11 +436,6 @@ std::ostream &operator<<(std::ostream &out, StreamRole role)
 	return out;
 }
 
-/**
- * \typedef StreamRoles
- * \brief A vector of StreamRole
- */
-
 /**
  * \class Stream
  * \brief Video stream for a camera