Bluetooth: hci_qca: use devm_clk_get_optional_enabled_with_rate()

Use the new devm_clk_get_optional_enabled_with_rate() clock helper to
shrink the code a bit.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>