Bluetooth: hci_qca: Replace devm_gpiod_get() with devm_gpiod_get_optional()

Bluetooth: hci_qca: Replace devm_gpiod_get() with devm_gpiod_get_optional()

This patch replaces devm_gpiod_get() with devm_gpiod_get_optional() to get
bt_en and replaces devm_clk_get() with devm_clk_get_optional() to get
susclk. It also uses NULL check to determine whether the resource is
available or not.

Fixes: e97b90cb94e4 ("Bluetooth: hci_qca: Make bt_en and susclk not mandatory for QCA Rome")
Signed-off-by: Rocky Liao <rjliao@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>