[PATCH 4/6] staging: comedi: don't allocate buffer space when polling for write

When handling the "poll" file operation and checking for `POLLOUT`, don't allocate space from the buffer for writing, just check that space is available for writing. That check is done after checking that an asynchronous "write" command is running on the subdevice. Allocating the buffer space

[PATCH 4/6] staging: comedi: don't allocate buffer space when polling for write

When handling the "poll" file operation and checking for `POLLOUT`, don't allocate space from the buffer for writing, just check that space is available for writing. That check is done after checking that an asynchronous "write" command is running on the subdevice. Allocating the buffer space