Fixed a few "-Wredundant-decls" warnings

[Sackzement]

Fixed these two warnings:

[ 28%] Building C object CMakeFiles/SDL3-shared.dir/src/audio/alsa/SDL_alsa_audio.c.o
/path/to/SDL/src/audio/alsa/SDL_alsa_audio.c:101:23: warning: redundant redeclaration of ‘ALSA_snd_pcm_info_get_subdevices_count’ [-Wredundant-decls]
  101 | static unsigned int (*ALSA_snd_pcm_info_get_subdevices_count)(const snd_pcm_info_t *);
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/path/to/SDL/src/audio/alsa/SDL_alsa_audio.c:96:23: note: previous declaration of ‘ALSA_snd_pcm_info_get_subdevices_count’ with type ‘unsigned int (*)(const snd_pcm_info_t *)’ {aka ‘unsigned int (*)(const struct _snd_pcm_info *)’}
   96 | static unsigned int (*ALSA_snd_pcm_info_get_subdevices_count)(const snd_pcm_info_t *);
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[ 43%] Building C object CMakeFiles/SDL3-shared.dir/src/haptic/hidapi/SDL_hidapihaptic.c.o
/path/to/SDL/src/haptic/hidapi/SDL_hidapihaptic.c:30:34: warning: redundant redeclaration of ‘SDL_HIDAPI_JoystickDriver’ [-Wredundant-decls]
   30 | extern struct SDL_JoystickDriver SDL_HIDAPI_JoystickDriver;
      |                                  ^~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /path/to/SDL/src/haptic/hidapi/SDL_hidapihaptic_c.h:29,
                 from /path/to/SDL/src/haptic/hidapi/SDL_hidapihaptic.c:26:
/path/to/SDL/src/haptic/hidapi/../../joystick/SDL_sysjoystick.h:253:27: note: previous declaration of ‘SDL_HIDAPI_JoystickDriver’ with type ‘SDL_JoystickDriver’
  253 | extern SDL_JoystickDriver SDL_HIDAPI_JoystickDriver;
      |                           ^~~~~~~~~~~~~~~~~~~~~~~~~