ice: initialize cached_phctime when creating Rx rings

When we create new Rx rings, the cached_phctime field is zero initialized.
This could result in incorrect timestamp reporting due to the cached value
not yet being updated. Although a background task will periodically update
the cached value, ensure it matches the existing cached value in the PF
structure at ring initialization.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>