ASoC: rt5645: Add mono speaker information to the components string

The GPD Win and Teclast X80 Pro both only have 1 speaker add information
about this to the components string.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://msgid.link/r/20231126214024.300505-7-hdegoede@redhat.com
Signed-off-by: Mark Brown <broonie@kernel.org>