pinctrl: Add pinctrl_pm_select_init_state helper function

pinctrl: Add pinctrl_pm_select_init_state helper function

If a platform requires an initial pinctrl state during probing, this
helper function provides the client with access to the same initial
state.

eg:
 xxx_suspend_noirq
    ...
    pinctrl_pm_select_sleep_state

 xxx resume_noirq
    pinctrl_pm_select_init_state
    ...
    pinctrl_pm_select_default_state

Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patch.msgid.link/20250820075411.1178729-3-christian.bruel@foss.st.com