Bluetooth: qca: use switch case for soc type behavior

Use switch/case to handle soc type specific behaviour,
the permit dropping the qca_is_xxx() inline functions
and make the code clearer and easier to update for new
SoCs.

Suggested-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Suggested-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>