PPP: fix build warning on wrong cast from void* to unsigned long

ppp/utils.c: In function 'ppp_vslprintf':
ppp/utils.c:251:12: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
     val = (unsigned long) va_arg(args, void *);
     ^

This is because a void* type is casted into an unsigned long type,
which obviously isn't correct on LLP64 systems such as Windows.

Actually, we are not using %p, thus we remove %p support completely
instead of trying to fix the issue in unused code.
1 file changed