clk: rs9: Fix suspend/resume

In the Linux kernel, the following vulnerability has been resolved: clk: rs9: Fix suspend/resume Disabling the cache in commit 2ff4ba9e3702 ("clk: rs9: Fix I2C accessors") without removing cache synchronization in resume path results in a kernel panic as map->cache_ops is unset, due to REGCACHE_NONE. Enable flat cache again to support resume again. num_reg_defaults_raw is necessary to read the cache defaults from hardware. Some registers are strapped in hardware and cannot be provided in software.