libcamera: Fix spellings and grammar

Fix a number of spelling errors and word duplications throughout the comments
within libcamera.

These were picked up with spellintian.

Also one capitalisation of the first word of a \return statement picked
up by checkstyle.py while creating this patch.

Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/camera.cpp

@@ -757,7 +757,7 @@ int Camera::freeBuffers()
  * \param[in] cookie Opaque cookie for application use
  *
  * This method creates an empty request for the application to fill with
- * buffers and paramaters, and queue for capture.
+ * buffers and parameters, and queue for capture.
  *
  * The \a cookie is stored in the request and is accessible through the
  * Request::cookie() method at any time. It is typically used by applications