tty: serial: qcom-geni-serial: improve the to_dev_port() macro

tty: serial: qcom-geni-serial: improve the to_dev_port() macro

The member we want to resolve in struct qcom_geni_serial_port is called
uport so we don't need an additional redundant parameter in this macro.

While at it: turn the macro into a static inline function.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20221229155030.418800-6-brgl@bgdev.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>