irqchip/st: Remove stih415/stih416 and stid127 platforms support

Remove support for the already no more supported stih415 and stih416
platforms.  Remove as well the stid127 platform which never made it
up to the kernel.

Signed-off-by: Alain Volmat <avolmat@me.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230416190501.18737-1-avolmat@me.com