man synopsis states [-n -logfile] option. Later on in avrdude.1 as well as in
main.c -l is used.
Also '-logfile' is no option alternative but a parameter.
This is a minor issue but still confusing when one uses / to search
through man pages.

-- Always leave the code cleaner than you found it --

Signed-off-by: brutzzl3r <s3b.gr0ss@gmail.com>

`avrdude.1` is installed into `man` dir instead of its proper section
location.
This is due to the definition of `TYPE MAN` which points to
`<DATAROOT>/man` according to cmake docs.

Use `DESTINATION` and add proper section subdir.

This allows for `man -M <YOUR INSTALL dir>/share/man -w 1 avrdude` to succeed
instead of throwing `No manual entry for avrdude in section 1`

Signed-off-by: brutzzl3r <s3b.gr0ss@gmail.com>