Add modules required to successfully boot the Lenovo Thinkpad T14s Gen 6 (Snapdragon X Elite). Changes: - Add rtc_pm8xxx module to initfs for RTC support - Add pinctrl_sm8550, as this is required for boot and the keyboard to work Tested-on: Lenovo Thinkpad T14s Gen 6 (21N1) Part-of: https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/6306