skl_print_pins() loops over all given pins but it overwrites the text
at the very same position while increasing the returned length.
Fix this to show the all pin contents properly.

Fixes: d14700a0 ("ASoC: Intel: Skylake: Debugfs facility to dump module config")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20200218111737.14193-2-tiwai@suse.deSigned-off-by: Mark Brown <broonie@kernel.org>