clk: rs9: Check for vendor/device ID

This is in preparation to support additional devices which have different
IDs as well as a slightly different register layout.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20230310075535.3476580-1-alexander.stein@ew.tq-group.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>