dt-bindings: net: realtek-bluetooth: Fix RTL8821CS binding

Update the fallback string for the RTL8821CS from realtek,rtl8822cs-bt
to realtek,rtl8723bs-bt. The difference between these two strings is
that the 8822cs enables power saving features that the 8723bs does not,
and in testing the 8821cs seems to have issues with these power saving
modes enabled.

Fixes: 95ee3a93 ("dt-bindings: net: realtek-bluetooth: Add RTL8821CS")
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20230508160811.3568213-2-macroalpha82@gmail.com


Signed-off-by: Rob Herring <robh@kernel.org>