net/tap-win32: Fix gcc 14 format truncation errors

net/tap-win32: Fix gcc 14 format truncation errors

The patch fixes the following errors generated by GCC 14.2:

../src/net/tap-win32.c:343:19: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 176 [-Werror=format-truncation=]
  343 |              "%s\\%s\\Connection",
      |                   ^~
  344 |              NETWORK_CONNECTIONS_KEY, enum_name);
      |                                       ~~~~~~~~~

../src/net/tap-win32.c:341:9: note: 'snprintf' output between 92 and 347 bytes into a destination of size 256
  341 |         snprintf(connection_string,
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~
  342 |              sizeof(connection_string),
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~
  343 |              "%s\\%s\\Connection",
      |              ~~~~~~~~~~~~~~~~~~~~~
  344 |              NETWORK_CONNECTIONS_KEY, enum_name);
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

../src/net/tap-win32.c:242:58: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 178 [-Werror=format-truncation=]
  242 |         snprintf (unit_string, sizeof(unit_string), "%s\\%s",
      |                                                          ^~
  243 |                   ADAPTER_KEY, enum_name);
      |                                ~~~~~~~~~

../src/net/tap-win32.c:242:9: note: 'snprintf' output between 79 and 334 bytes into a destination of size 256
  242 |         snprintf (unit_string, sizeof(unit_string), "%s\\%s",
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  243 |                   ADAPTER_KEY, enum_name);
      |                   ~~~~~~~~~~~~~~~~~~~~~~~

../src/net/tap-win32.c:620:52: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 245 [-Werror=format-truncation=]
  620 |     snprintf (device_path, sizeof(device_path), "%s%s%s",
      |                                                    ^~
  621 |               USERMODEDEVICEDIR,
  622 |               device_guid,
      |               ~~~~~~~~~~~
../src/net/tap-win32.c:620:5: note: 'snprintf' output between 16 and 271 bytes into a destination of size 256
  620 |     snprintf (device_path, sizeof(device_path), "%s%s%s",
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  621 |               USERMODEDEVICEDIR,
      |               ~~~~~~~~~~~~~~~~~~
  622 |               device_guid,
      |               ~~~~~~~~~~~~
  623 |               TAPSUFFIX);
      |               ~~~~~~~~~~

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2607
Cc: qemu-stable@nongnu.org
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>