ss: initialise variables outside of for loop

ss: initialise variables outside of for loop

Initialise for loops outside of for loops. GCC flags this as being
out of spec unless C99 or C11 mode is used.

With this change the entire tree appears to compile cleanly with -Wall.

$ gcc --version
gcc (Debian 4.9.2-10) 4.9.2
...
$ make
...
ss.c: In function ‘unix_show_sock’:
ss.c:3128:4: error: ‘for’ loop initial declarations are only allowed in C99 or C11 mode
...

Signed-off-by: Simon Horman <simon.horman@netronome.com>