fdcontrol/fdcontrol.c:
	- Add const constraint to an intermediate value
	  which is not supposed to be changed elsewhere.
fdread/fdread.c:
	- Use _devname in favor of devname to avoid name
	  conflicit.
	- -1 is less than any positive number so in order
	  to get the block to function, we should get the
	  block a little earlier.
	- Cast to remove signed when we are sure that a
	  return value is positive, or is compared with
	  an positive number (tracknumber of a floppy
	  disk is not likely to have UINT_MAX/2 anyway)
fdread/fdutil.c:
	- Use more specific initializer
fdwrite/fdwrite.c:
	- Use static on format_track since it's not
	  referenced in other places.
	- Use const char* to represent string constant.

Bump WARNS accordingly.

Approved by:	das (mentor)

Avoid using parenthesis enclosure macros (.Pq and .Po/.Pc) with plain text.
Not only this slows down the mdoc(7) processing significantly, but it also
has an undesired (in this case) effect of disabling hyphenation within the
entire enclosed block.

These are not perfectly in agreement with each other style-wise, but they
are orders of orders of magnitude more consistent style-wise than before.