tools: gpio: fix %llu warning in gpio-watch.c

Some platforms, such as mips64, don't map __u64 to long long unsigned
int so using %llu produces a warning:

gpio-watch.c: In function ‘main’:
gpio-watch.c:89:30: warning: format ‘%llu’ expects argument of type ‘long long unsigned int’, but argument 4 has type ‘__u64’ {aka ‘long unsigned int’} [-Wformat=]
89 | printf("line %u: %s at %llu\n",
| ~~~^
| |
| long long unsigned int
| %lu
90 | chg.info.offset, event, chg.timestamp_ns);
| ~~~~~~~~~~~~~~~~
| |
| __u64 {aka long unsigned int}

Replace the %llu with PRIu64 and cast the argument to uint64_t.

Fixes: 33f0c47b8fb4 ("tools: gpio: implement gpio-watch")
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

tools: gpio: port gpio-watch to v2 uAPI

Port the gpio-watch tool to the latest GPIO uAPI.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

tools: gpio: implement gpio-watch

Add a simple program that allows to test the new LINECHANGED_FD ioctl().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>