ASoC: imx-audmux: Silence a clang warning

ASoC: imx-audmux: Silence a clang warning

Change the of_device_get_match_data() cast to (uintptr_t)
to silence the following clang warning:

sound/soc/fsl/imx-audmux.c:301:16: warning: cast to smaller integer type 'enum imx_audmux_type' from 'const void *' [-Wvoid-pointer-to-enum-cast]

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 99429f966d5c ("ASoC: imx-audmux: Remove unused .id_table")
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20220526010543.1164793-1-festevam@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>