net/ice/base: remove Rx flex descriptor programming

Removing Rx flex descriptor metadata and flag programming from the code,
these registers cannot be written to as they are read only.
The programming for all fields per RxDID is now handled differently.

Signed-off-by: Vignesh Sridhar <vignesh.sridhar@intel.com>
Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Xiaolong Ye <xiaolong.ye@intel.com>