Bluetooth: hci_sync: Simplify hci_reset_sync()

Return the reset command status directly instead of storing it in a
local variable and using an if/return pattern.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>