kselftest/alsa - mixer-test: Fix the print format specifier warning

kselftest/alsa - mixer-test: Fix the print format specifier warning

GCC 13.2.0 compiler issued the following warning:

mixer-test.c:350:80: warning: format ‘%ld’ expects argument of type ‘long int’, \
			      but argument 5 has type ‘unsigned int’ [-Wformat=]
  350 |                         ksft_print_msg("%s.%d value %ld more than item count %ld\n",
      |                                                                              ~~^
      |                                                                                |
      |                                                                                long int
      |                                                                              %d
  351 |                                        ctl->name, index, int_val,
  352 |                                        snd_ctl_elem_info_get_items(ctl->info));
      |                                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                                        |
      |                                        unsigned int

Fixing the format specifier in call to ksft_print_msg() according to the
compiler suggestion silences the warning.

Fixes: 10f2f194663af ("kselftest: alsa: Validate values read from enumerations")
Cc: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-sound@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240107173704.937824-4-mirsad.todorovac@alu.unizg.hr
Signed-off-by: Takashi Iwai <tiwai@suse.de>