clk: keystone: sci-clk: Add restore_context() operation

clk: keystone: sci-clk: Add restore_context() operation

Implement the restore_context() operation to restore the clock rate
and the clock parent state. The clock rate is saved in sci_clk struct
during set_rate() and recalc_rate() operations. The parent index
is saved in sci_clk struct during set_parent() operation. During
clock registration, the core retrieves each clock’s parent using
get_parent() operation to ensure the internal clock tree reflects
the actual hardware state, including any configurations made by the
bootloader. So we also save the parent index in get_parent().

Reviewed-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Kendall Willis <k-willis@ti.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Reviewed-by: Brian Masney <bmasney@redhat.com>
Signed-off-by: Thomas Richard (TI) <thomas.richard@bootlin.com>
Link: https://patch.msgid.link/20260519-ti-sci-jacinto-s2r-restore-irq-v9-3-c550a8ae0f31@bootlin.com
Signed-off-by: Nishanth Menon <nm@ti.com>