net-snmp: fix PRIdPTR macro undefined error

net-snmp: fix PRIdPTR macro undefined error

This commit includes inttypes.h to prevent the following error:

```
mibgroup/ieee802dot11.c: In function 'displayWiExt':
mibgroup/ieee802dot11.c:4563:26: error: expected ')' before 'PRIdPTR'
 4563 |     printf ( "%s sens: %" PRIdPTR "\n", "SIOCGIWSENS", *(intptr_t *)&info.sens );
      |            ~             ^~~~~~~~
      |                          )
mibgroup/ieee802dot11.c:31:1: note: 'PRIdPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?
   30 | #include "util_funcs/header_generic.h"
  +++ |+#include <inttypes.h>
   31 |
```

Signed-off-by: Wei-Ting Yang <[email protected]>